Nadav Amit [Wed, 18 Jun 2014 14:19:35 +0000 (17:19 +0300)]
KVM: x86: Emulator support for #UD on CPL>0
Certain instructions (e.g., mwait and monitor) cause a #UD exception when they
are executed in user mode. This is in contrast to the regular privileged
instructions which cause #GP. In order not to mess with SVM interception of
mwait and monitor which assumes privilege level assertions take place before
interception, a flag has been added.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Wed, 18 Jun 2014 14:19:34 +0000 (17:19 +0300)]
KVM: x86: Emulator flag for instruction that only support 16-bit addresses in real mode
Certain instructions, such as monitor and xsave do not support big real mode
and cause a #GP exception if any of the accessed bytes effective address are
not within [0, 0xffff]. This patch introduces a flag to mark these
instructions, including the necassary checks.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 13 May 2014 12:02:13 +0000 (14:02 +0200)]
KVM: x86: use kvm_read_guest_page for emulator accesses
Emulator accesses are always done a page at a time, either by the emulator
itself (for fetches) or because we need to query the MMU for address
translations. Speed up these accesses by using kvm_read_guest_page
and, in the case of fetches, by inlining kvm_read_guest_virt_helper and
dropping the loop around kvm_read_guest_page.
This final tweak saves 30-100 more clock cycles (4-10%), bringing the
count (as measured by kvm-unit-tests) down to 720-1100 clock cycles on
a Sandy Bridge Xeon host, compared to 2300-3200 before the whole series
and 925-1700 after the first two low-hanging fruit changes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 19 Jun 2014 09:37:06 +0000 (11:37 +0200)]
KVM: x86: ensure emulator fetches do not span multiple pages
When the CS base is not page-aligned, the linear address of the code could
get close to the page boundary (e.g. 0x...ffe) even if the EIP value is
not. So we need to first linearize the address, and only then compute
the number of valid bytes that can be fetched.
This happens relatively often when executing real mode code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 6 May 2014 11:05:25 +0000 (13:05 +0200)]
KVM: emulate: avoid per-byte copying in instruction fetches
We do not need a memory copying loop anymore in insn_fetch; we
can use a byte-aligned pointer to access instruction fields directly
from the fetch_cache. This eliminates 50-150 cycles (corresponding to
a 5-10% improvement in performance) from each instruction.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 6 May 2014 11:05:25 +0000 (13:05 +0200)]
KVM: emulate: avoid repeated calls to do_insn_fetch_bytes
do_insn_fetch_bytes will only be called once in a given insn_fetch and
insn_fetch_arr, because in fact it will only be called at most twice
for any instruction and the first call is explicit in x86_decode_insn.
This observation lets us hoist the call out of the memory copying loop.
It does not buy performance, because most fetches are one byte long
anyway, but it prepares for the next patch.
The overflow check is tricky, but correct. Because do_insn_fetch_bytes
has already been called once, we know that fc->end is at least 15. So
it is okay to subtract the number of bytes we want to read.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 6 May 2014 10:24:32 +0000 (12:24 +0200)]
KVM: emulate: speed up do_insn_fetch
Hoist the common case up from do_insn_fetch_byte to do_insn_fetch,
and prime the fetch_cache in x86_decode_insn. This helps a bit the
compiler and the branch predictor, but above all it lays the
ground for further changes in the next few patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bandan Das [Wed, 16 Apr 2014 16:46:14 +0000 (12:46 -0400)]
KVM: emulate: do not initialize memopp
rip_relative is only set if decode_modrm runs, and if you have ModRM
you will also have a memopp. We can then access memopp unconditionally.
Note that rip_relative cannot be hoisted up to decode_modrm, or you
break "mov $0, xyz(%rip)".
Also, move typecast on "out of range value" of mem.ea to decode_modrm.
Together, all these optimizations save about 50 cycles on each emulated
instructions (4-6%).
Signed-off-by: Bandan Das <bsd@redhat.com>
[Fix immediate operands with rip-relative addressing. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bandan Das [Wed, 16 Apr 2014 16:46:13 +0000 (12:46 -0400)]
KVM: emulate: rework seg_override
x86_decode_insn already sets a default for seg_override,
so remove it from the zeroed area. Also replace set/get functions
with direct access to the field.
Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bandan Das [Wed, 16 Apr 2014 16:46:12 +0000 (12:46 -0400)]
KVM: emulate: clean up initializations in init_decode_cache
A lot of initializations are unnecessary as they get set to
appropriate values before actually being used. Optimize
placement of fields in x86_emulate_ctxt
Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 27 Mar 2014 10:36:25 +0000 (11:36 +0100)]
KVM: emulate: speed up emulated moves
We can just blindly move all 16 bytes of ctxt->src's value to ctxt->dst.
write_register_operand will take care of writing only the lower bytes.
Avoiding a call to memcpy (the compiler optimizes it out) gains about
200 cycles on kvm-unit-tests for register-to-register moves, and makes
them about as fast as arithmetic instructions.
We could perhaps get a larger speedup by moving all instructions _except_
moves out of x86_emulate_insn, removing opcode_len, and replacing the
switch statement with an inlined em_mov.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 27 Mar 2014 10:58:02 +0000 (11:58 +0100)]
KVM: emulate: protect checks on ctxt->d by a common "if (unlikely())"
There are several checks for "peculiar" aspects of instructions in both
x86_decode_insn and x86_emulate_insn. Group them together, and guard
them with a single "if" that lets the processor quickly skip them all.
Make this more effective by adding two more flag bits that say whether the
.intercept and .check_perm fields are valid. We will reuse these
flags later to avoid initializing fields of the emulate_ctxt struct.
This skims about 30 cycles for each emulated instructions, which is
approximately a 3% improvement.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 27 Mar 2014 10:29:28 +0000 (11:29 +0100)]
KVM: x86: avoid useless set of KVM_REQ_EVENT after emulation
Despite the provisions to emulate up to 130 consecutive instructions, in
practice KVM will emulate just one before exiting handle_invalid_guest_state,
because x86_emulate_instruction always sets KVM_REQ_EVENT.
However, we only need to do this if an interrupt could be injected,
which happens a) if an interrupt shadow bit (STI or MOV SS) has gone
away; b) if the interrupt flag has just been set (other instructions
than STI can set it without enabling an interrupt shadow).
This cuts another 700-900 cycles from the cost of emulating an
instruction (measured on a Sandy Bridge Xeon: 1650-2600 cycles
before the patch on kvm-unit-tests, 925-1700 afterwards).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 20 May 2014 12:29:47 +0000 (14:29 +0200)]
KVM: x86: return all bits from get_interrupt_shadow
For the next patch we will need to know the full state of the
interrupt shadow; we will then set KVM_REQ_EVENT when one bit
is cleared.
However, right now get_interrupt_shadow only returns the one
corresponding to the emulated instruction, or an unconditional
0 if the emulated instruction does not have an interrupt shadow.
This is confusing and does not allow us to check for cleared
bits as mentioned above.
Clean the callback up, and modify toggle_interruptibility to
match the comment above the call. As a small result, the
call to set_interrupt_shadow will be skipped in the common
case where int_shadow == 0 && mask == 0.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 27 Mar 2014 08:51:52 +0000 (09:51 +0100)]
KVM: vmx: speed up emulation of invalid guest state
About 25% of the time spent in emulation of invalid guest state
is wasted in checking whether emulation is required for the next
instruction. However, this almost never changes except when a
segment register (or TR or LDTR) changes, or when there is a mode
transition (i.e. CR0 changes).
In fact, vmx_set_segment and vmx_set_cr0 already modify
vmx->emulation_required (except that the former for some reason
uses |= instead of just an assignment). So there is no need to
call guest_state_valid in the emulation loop.
Emulation performance test results indicate 1650-2600 cycles
for common instructions, versus 2300-3200 before this patch on
a Sandy Bridge Xeon.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Matthias Lange [Thu, 26 Jun 2014 11:50:15 +0000 (13:50 +0200)]
KVM: svm: writes to MSR_K7_HWCR generates GPE in guest
Since commit 575203 the MCE subsystem in the Linux kernel for AMD sets bit 18
in MSR_K7_HWCR. Running such a kernel as a guest in KVM on an AMD host results
in a GPE injected into the guest because kvm_set_msr_common returns 1. This
patch fixes this by masking bit 18 from the MSR value desired by the guest.
Signed-off-by: Matthias Lange <matthias.lange@kernkonzept.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 30 Jun 2014 09:03:02 +0000 (12:03 +0300)]
KVM: x86: Pending interrupt may be delivered after INIT
We encountered a scenario in which after an INIT is delivered, a pending
interrupt is delivered, although it was sent before the INIT. As the SDM
states in section 10.4.7.1, the ISR and the IRR should be cleared after INIT as
KVM does. This also means that pending interrupts should be cleared. This
patch clears upon reset (and INIT) the pending interrupts; and at the same
occassion clears the pending exceptions, since they may cause a similar issue.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jim Mattson [Tue, 8 Jul 2014 04:17:41 +0000 (09:47 +0530)]
KVM: Synthesize G bit for all segments.
We have noticed that qemu-kvm hangs early in the BIOS when runnning nested
under some versions of VMware ESXi.
The problem we believe is because KVM assumes that the platform preserves
the 'G' but for any segment register. The SVM specification itemizes the
segment attribute bits that are observed by the CPU, but the (G)ranularity bit
is not one of the bits itemized, for any segment. Though current AMD CPUs keep
track of the (G)ranularity bit for all segment registers other than CS, the
specification does not require it. VMware's virtual CPU may not track the
(G)ranularity bit for any segment register.
Since kvm already synthesizes the (G)ranularity bit for the CS segment. It
should do so for all segments. The patch below does that, and helps get rid of
the hangs. Patch applies on top of Linus' tree.
Signed-off-by: Jim Mattson <jmattson@vmware.com> Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
James Hogan [Fri, 4 Jul 2014 14:11:35 +0000 (15:11 +0100)]
KVM: MIPS: Document MIPS specifics of KVM API.
Document the MIPS specific parts of the KVM API, including:
- The layout of the kvm_regs structure.
- The interrupt number passed to KVM_INTERRUPT.
- The registers supported by the KVM_{GET,SET}_ONE_REG interface, and
the encoding of those register ids.
- That KVM_INTERRUPT and KVM_GET_REG_LIST are supported on MIPS.
Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-doc@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some of the MIPS registers that can be accessed with the
KVM_{GET,SET}_ONE_REG interface have fairly long names, so widen the
Register column of the table in the KVM_SET_ONE_REG documentation to
allow them to fit.
Tabs in the table are replaced with spaces at the same time for
consistency.
Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-doc@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Tomasz Grabiec [Tue, 24 Jun 2014 07:42:43 +0000 (09:42 +0200)]
KVM: x86: fix TSC matching
I've observed kvmclock being marked as unstable on a modern
single-socket system with a stable TSC and qemu-1.6.2 or qemu-2.0.0.
The culprit was failure in TSC matching because of overflow of
kvm_arch::nr_vcpus_matched_tsc in case there were multiple TSC writes
in a single synchronization cycle.
Turns out that qemu does multiple TSC writes during init, below is the
evidence of that (qemu-2.0.0):
#0 kvm_vcpu_ioctl at /build/buildd/qemu-2.0.0+dfsg/kvm-all.c:1780
#1 kvm_put_msrs at /build/buildd/qemu-2.0.0+dfsg/target-i386/kvm.c:1270
#2 kvm_arch_put_registers at /build/buildd/qemu-2.0.0+dfsg/target-i386/kvm.c:1909
#3 kvm_cpu_synchronize_post_init at /build/buildd/qemu-2.0.0+dfsg/kvm-all.c:1641
#4 cpu_synchronize_post_init at /build/buildd/qemu-2.0.0+dfsg/include/sysemu/kvm.h:330
#5 cpu_synchronize_all_post_init () at /build/buildd/qemu-2.0.0+dfsg/cpus.c:521
#6 main at /build/buildd/qemu-2.0.0+dfsg/vl.c:4390
#0 kvm_vcpu_ioctl at /build/buildd/qemu-2.0.0+dfsg/kvm-all.c:1780
#1 kvm_put_msrs at /build/buildd/qemu-2.0.0+dfsg/target-i386/kvm.c:1270
#2 kvm_arch_put_registers at /build/buildd/qemu-2.0.0+dfsg/target-i386/kvm.c:1909
#3 kvm_cpu_synchronize_post_reset at /build/buildd/qemu-2.0.0+dfsg/kvm-all.c:1635
#4 cpu_synchronize_post_reset at /build/buildd/qemu-2.0.0+dfsg/include/sysemu/kvm.h:323
#5 cpu_synchronize_all_post_reset () at /build/buildd/qemu-2.0.0+dfsg/cpus.c:512
#6 main at /build/buildd/qemu-2.0.0+dfsg/vl.c:4482
The fix is to count each vCPU only once when matched, so that
nr_vcpus_matched_tsc holds the size of the matched set. This is
achieved by reusing generation counters. Every vCPU with
this_tsc_generation == cur_tsc_generation is in the matched set. The
match set is cleared by setting cur_tsc_generation to a value which no
other vCPU is set to (by incrementing it).
I needed to bump up the counter size form u8 to u64 to ensure it never
overflows. Otherwise in cases TSC is not written the same number of
times on each vCPU the counter could overflow and incorrectly indicate
some vCPUs as being in the matched set. This scenario seems unlikely
but I'm not sure if it can be disregarded.
Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Mon, 30 Jun 2014 10:52:55 +0000 (12:52 +0200)]
KVM: nSVM: Set correct port for IOIO interception evaluation
Obtaining the port number from DX is bogus as a) there are immediate
port accesses and b) user space may have changed the register content
while processing the PIO access. Forward the correct value from the
instruction emulator instead.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Mon, 30 Jun 2014 08:54:17 +0000 (10:54 +0200)]
KVM: nSVM: Fix IOIO bitmap evaluation
First, kvm_read_guest returns 0 on success. And then we need to take the
access size into account when testing the bitmap: intercept if any of
bits corresponding to the access is set.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Sun, 29 Jun 2014 19:55:53 +0000 (21:55 +0200)]
KVM: nSVM: Do not report CLTS via SVM_EXIT_WRITE_CR0 to L1
CLTS only changes TS which is not monitored by selected CR0
interception. So skip any attempt to translate WRITE_CR0 to
CR0_SEL_WRITE for this instruction.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Sun, 29 Jun 2014 15:12:43 +0000 (17:12 +0200)]
KVM: SVM: Fix CPL export via SS.DPL
We import the CPL via SS.DPL since ae9fedc793. However, we fail to
export it this way so far. This caused spurious guest crashes, e.g. of
Linux when accessing the vmport from guest user space which triggered
register saving/restoring to/from host user space.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Heiko Carstens [Thu, 5 Jun 2014 11:22:49 +0000 (13:22 +0200)]
KVM: s390: add sie.h uapi header file to Kbuild and remove header dependency
sie.h was missing in arch/s390/include/uapi/asm/Kbuild and therefore missed
the "make headers_check" target.
If added it reveals that also arch/s390/include/asm/sigp.h would become uapi.
This is something we certainly do not want. So remove that dependency as well.
The header file was merged with ceae283bb2e0176c "KVM: s390: add sie exit
reasons tables", therefore we never had a kernel release with this commit and
can still change anything.
Nadav Amit [Wed, 18 Jun 2014 14:19:26 +0000 (17:19 +0300)]
KVM: vmx: vmx instructions handling does not consider cs.l
VMX instructions use 32-bit operands in 32-bit mode, and 64-bit operands in
64-bit mode. The current implementation is broken since it does not use the
register operands correctly, and always uses 64-bit for reads and writes.
Moreover, write to memory in vmwrite only considers long-mode, so it ignores
cs.l. This patch fixes this behavior.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Wed, 18 Jun 2014 14:19:25 +0000 (17:19 +0300)]
KVM: vmx: handle_cr ignores 32/64-bit mode
On 32-bit mode only bits [31:0] of the CR should be used for setting the CR
value. Otherwise, the host may incorrectly assume the value is invalid if bits
[63:32] are not zero. Moreover, the CR is currently being read twice when CR8
is used. Last, nested mov-cr exiting is modified to handle the CR value
correctly as well.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Wed, 18 Jun 2014 14:19:24 +0000 (17:19 +0300)]
KVM: x86: Hypercall handling does not considers opsize correctly
Currently, the hypercall handling routine only considers LME as an indication
to whether the guest uses 32/64-bit mode. This is incosistent with hyperv
hypercalls handling and against the common sense of considering cs.l as well.
This patch uses is_64_bit_mode instead of is_long_mode for that matter. In
addition, the result is masked in respect to the guest execution mode. Last, it
changes kvm_hv_hypercall to use is_64_bit_mode as well to simplify the code.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Wed, 18 Jun 2014 14:19:23 +0000 (17:19 +0300)]
KVM: x86: check DR6/7 high-bits are clear only on long-mode
When the guest sets DR6 and DR7, KVM asserts the high 32-bits are clear, and
otherwise injects a #GP exception. This exception should only be injected only
if running in long-mode.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Mon, 16 Jun 2014 11:59:43 +0000 (13:59 +0200)]
KVM: nVMX: Allow to disable VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS
Allow L1 to "leak" its debug controls into L2, i.e. permit cleared
VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS. This requires to manually
transfer the state of DR7 and IA32_DEBUGCTLMSR from L1 into L2 as both
run on different VMCS.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Mon, 16 Jun 2014 11:59:41 +0000 (13:59 +0200)]
KVM: nVMX: Allow to disable CR3 access interception
We already have this control enabled by exposing a broken
MSR_IA32_VMX_PROCBASED_CTLS value. This will properly advertise our
capability once the value is fixed by clearing the right bits in
MSR_IA32_VMX_TRUE_PROCBASED_CTLS. We also have to ensure to test the
right value on L2 entry.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Mon, 16 Jun 2014 11:59:40 +0000 (13:59 +0200)]
KVM: nVMX: Advertise support for MSR_IA32_VMX_TRUE_*_CTLS
We already implemented them but failed to advertise them. Currently they
all return the identical values to the capability MSRs they are
augmenting. So there is no change in exposed features yet.
Drop related comments at this chance that are partially incorrect and
redundant anyway.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jan Kiszka [Thu, 12 Jun 2014 17:40:32 +0000 (19:40 +0200)]
KVM: x86: Fix constant value of VM_{EXIT_SAVE,ENTRY_LOAD}_DEBUG_CONTROLS
The spec says those controls are at bit position 2 - makes 4 as value.
The impact of this mistake is effectively zero as we only use them to
ensure that these features are set at position 2 (or, previously, 1) in
MSR_IA32_VMX_{EXIT,ENTRY}_CTLS - which is and will be always true
according to the spec.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Sun, 15 Jun 2014 13:13:00 +0000 (16:13 +0300)]
KVM: x86: emulation of dword cmov on long-mode should clear [63:32]
Even if the condition of cmov is not satisfied, bits[63:32] should be cleared.
This is clearly stated in Intel's CMOVcc documentation. The solution is to
reassign the destination onto itself if the condition is unsatisfied. For that
matter the original destination value needs to be read.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Sun, 15 Jun 2014 13:12:59 +0000 (16:12 +0300)]
KVM: x86: Inter-privilege level ret emulation is not implemeneted
Return unhandlable error on inter-privilege level ret instruction. This is
since the current emulation does not check the privilege level correctly when
loading the CS, and does not pop RSP/SS as needed.
Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Sun, 15 Jun 2014 13:12:58 +0000 (16:12 +0300)]
KVM: x86: Wrong emulation on 'xadd X, X'
The emulator does not emulate the xadd instruction correctly if the two
operands are the same. In this (unlikely) situation the result should be the
sum of X and X (2X) when it is currently X. The solution is to first perform
writeback to the source, before writing to the destination. The only
instruction which should be affected is xadd, as the other instructions that
perform writeback to the source use the extended accumlator (e.g., RAX:RDX).
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 2 Jun 2014 15:34:11 +0000 (18:34 +0300)]
KVM: x86: smsw emulation is incorrect in 64-bit mode
In 64-bit mode, when the destination is a register, the assignment is done
according to the operand size. Otherwise (memory operand or no 64-bit mode), a
16-bit assignment is performed.
Currently, 16-bit assignment is always done to the destination.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 2 Jun 2014 15:34:09 +0000 (18:34 +0300)]
KVM: x86: rdpmc emulation checks the counter incorrectly
The rdpmc emulation checks that the counter (ECX) is not higher than 2, without
taking into considerations bits 30:31 role (e.g., bit 30 marks whether the
counter is fixed). The fix uses the pmu information for checking the validity
of the pmu counter.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 2 Jun 2014 15:34:07 +0000 (18:34 +0300)]
KVM: x86: cmpxchg emulation should compare in reverse order
The current implementation of cmpxchg does not update the flags correctly,
since the accumulator should be compared with the destination and not the other
way around. The current implementation does not update the flags correctly.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 2 Jun 2014 15:34:05 +0000 (18:34 +0300)]
KVM: x86: Loading segments on 64-bit mode may be wrong
The current emulator implementation ignores the high 32 bits of the base in
long-mode. During segment load from the LDT, the base of the LDT is calculated
incorrectly and may cause the wrong segment to be loaded.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Nadav Amit [Mon, 2 Jun 2014 15:34:03 +0000 (18:34 +0300)]
KVM: x86: Mark VEX-prefix instructions emulation as unimplemented
Currently the emulator does not recognize vex-prefix instructions. However, it
may incorrectly decode lgdt/lidt instructions and try to execute them. This
patch returns unhandlable error on their emulation.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1) Fix checksumming regressions, from Tom Herbert.
2) Undo unintentional permissions changes for SCTP rto_alpha and
rto_beta sysfs knobs, from Denial Borkmann.
3) VXLAN, like other IP tunnels, should advertize it's encapsulation
size using dev->needed_headroom instead of dev->hard_header_len.
From Cong Wang.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: sctp: fix permissions for rto_alpha and rto_beta knobs
vxlan: Checksum fixes
net: add skb_pop_rcv_encapsulation
udp: call __skb_checksum_complete when doing full checksum
net: Fix save software checksum complete
net: Fix GSO constants to match NETIF flags
udp: ipv4: do not waste time in __udp4_lib_mcast_demux_lookup
vxlan: use dev->needed_headroom instead of dev->hard_header_len
MAINTAINERS: update cxgb4 maintainer
Linus Torvalds [Mon, 16 Jun 2014 02:02:20 +0000 (16:02 -1000)]
Merge tag 'clk-for-linus-3.16-part2' of git://git.linaro.org/people/mike.turquette/linux
Pull more clock framework updates from Mike Turquette:
"This contains the second half the of the clk changes for 3.16.
They are simply fixes and code refactoring for the OMAP clock drivers.
The sunxi clock driver changes include splitting out the one
mega-driver into several smaller pieces and adding support for the A31
SoC clocks"
* tag 'clk-for-linus-3.16-part2' of git://git.linaro.org/people/mike.turquette/linux: (25 commits)
clk: sunxi: document PRCM clock compatible strings
clk: sunxi: add PRCM (Power/Reset/Clock Management) clks support
clk: sun6i: Protect SDRAM gating bit
clk: sun6i: Protect CPU clock
clk: sunxi: Rework clock protection code
clk: sunxi: Move the GMAC clock to a file of its own
clk: sunxi: Move the 24M oscillator to a file of its own
clk: sunxi: Remove calls to clk_put
clk: sunxi: document new A31 USB clock compatible
clk: sunxi: Implement A31 USB clock
ARM: dts: OMAP5/DRA7: use omap5-mpu-dpll-clock capable of dealing with higher frequencies
CLK: TI: dpll: support OMAP5 MPU DPLL that need special handling for higher frequencies
ARM: OMAP5+: dpll: support Duty Cycle Correction(DCC)
CLK: TI: clk-54xx: Set the rate for dpll_abe_m2x2_ck
CLK: TI: Driver for DRA7 ATL (Audio Tracking Logic)
dt:/bindings: DRA7 ATL (Audio Tracking Logic) clock bindings
ARM: dts: dra7xx-clocks: Correct name for atl clkin3 clock
CLK: TI: gate: add composite interface clock to OMAP2 only build
ARM: OMAP2: clock: add DT boot support for cpufreq_ck
CLK: TI: OMAP2: add clock init support
...
Pull NVMe update from Matthew Wilcox:
"Mostly bugfixes again for the NVMe driver. I'd like to call out the
exported tracepoint in the block layer; I believe Keith has cleared
this with Jens.
We've had a few reports from people who're really pounding on NVMe
devices at scale, hence the timeout changes (and new module
parameters), hotplug cpu deadlock, tracepoints, and minor performance
tweaks"
[ Jens hadn't seen that tracepoint thing, but is ok with it - it will
end up going away when mq conversion happens ]
* git://git.infradead.org/users/willy/linux-nvme: (22 commits)
NVMe: Fix START_STOP_UNIT Scsi->NVMe translation.
NVMe: Use Log Page constants in SCSI emulation
NVMe: Define Log Page constants
NVMe: Fix hot cpu notification dead lock
NVMe: Rename io_timeout to nvme_io_timeout
NVMe: Use last bytes of f/w rev SCSI Inquiry
NVMe: Adhere to request queue block accounting enable/disable
NVMe: Fix nvme get/put queue semantics
NVMe: Delete NVME_GET_FEAT_TEMP_THRESH
NVMe: Make admin timeout a module parameter
NVMe: Make iod bio timeout a parameter
NVMe: Prevent possible NULL pointer dereference
NVMe: Fix the buffer size passed in GetLogPage(CDW10.NUMD)
NVMe: Update data structures for NVMe 1.2
NVMe: Enable BUILD_BUG_ON checks
NVMe: Update namespace and controller identify structures to the 1.1a spec
NVMe: Flush with data support
NVMe: Configure support for block flush
NVMe: Add tracepoints
NVMe: Protect against badly formatted CQEs
...
Daniel Borkmann [Sat, 14 Jun 2014 22:59:14 +0000 (00:59 +0200)]
net: sctp: fix permissions for rto_alpha and rto_beta knobs
Commit 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs
to jiffies conversions.") has silently changed permissions for
rto_alpha and rto_beta knobs from 0644 to 0444. The purpose of
this was to discourage users from tweaking rto_alpha and
rto_beta knobs in production environments since they are key
to correctly compute rtt/srtt.
RFC4960 under section 6.3.1. RTO Calculation says regarding
rto_alpha and rto_beta under rule C3 and C4:
[...]
C3) When a new RTT measurement R' is made, set
Note: The value of SRTT used in the update to RTTVAR
is its value before updating SRTT itself using the
second assignment. After the computation, update
RTO <- SRTT + 4 * RTTVAR.
C4) When data is in flight and when allowed by rule C5
below, a new RTT measurement MUST be made each round
trip. Furthermore, new RTT measurements SHOULD be
made no more than once per round trip for a given
destination transport address. There are two reasons
for this recommendation: First, it appears that
measuring more frequently often does not in practice
yield any significant benefit [ALLMAN99]; second,
if measurements are made more often, then the values
of RTO.Alpha and RTO.Beta in rule C3 above should be
adjusted so that SRTT and RTTVAR still adjust to
changes at roughly the same rate (in terms of how many
round trips it takes them to reflect new values) as
they would if making only one measurement per
round-trip and using RTO.Alpha and RTO.Beta as given
in rule C3. However, the exact nature of these
adjustments remains a research issue.
[...]
While it is discouraged to adjust rto_alpha and rto_beta
and not further specified how to adjust them, the RFC also
doesn't explicitly forbid it, but rather gives a RECOMMENDED
default value (rto_alpha=3, rto_beta=2). We have a couple
of users relying on the old permissions before they got
changed. That said, if someone really has the urge to adjust
them, we could allow it with a warning in the log.
Fixes: 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
David S. Miller [Sun, 15 Jun 2014 08:00:56 +0000 (01:00 -0700)]
Merge branch 'csum_fixes'
Tom Herbert says:
====================
Fixes related to some recent checksum modifications.
- Fix GSO constants to match NETIF flags
- Fix logic in saving checksum complete in __skb_checksum_complete
- Call __skb_checksum_complete from UDP if we are checksumming over
whole packet in order to save checksum.
- Fixes to VXLAN to work correctly with checksum complete
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Tom Herbert [Sun, 15 Jun 2014 06:24:28 +0000 (23:24 -0700)]
net: add skb_pop_rcv_encapsulation
This function is used by UDP encapsulation protocols in RX when
crossing encapsulation boundary. If ip_summed is set to
CHECKSUM_UNNECESSARY and encapsulation is not set, change to
CHECKSUM_NONE since the checksum has not been validated within the
encapsulation. Clears csum_valid by the same rationale.
Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Tom Herbert [Sun, 15 Jun 2014 06:24:20 +0000 (23:24 -0700)]
udp: call __skb_checksum_complete when doing full checksum
In __udp_lib_checksum_complete check if checksum is being done over all
the data (len is equal to skb->len) and if it is call
__skb_checksum_complete instead of __skb_checksum_complete_head. This
allows checksum to be saved in checksum complete.
Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Tom Herbert [Sun, 15 Jun 2014 06:24:03 +0000 (23:24 -0700)]
net: Fix save software checksum complete
Geert reported issues regarding checksum complete and UDP.
The logic introduced in commit 7e3cead5172927732f51fde
("net: Save software checksum complete") is not correct.
This patch:
1) Restores code in __skb_checksum_complete_header except for setting
CHECKSUM_UNNECESSARY. This function may be calculating checksum on
something less than skb->len.
2) Adds saving checksum to __skb_checksum_complete. The full packet
checksum 0..skb->len is calculated without adding in pseudo header.
This value is saved in skb->csum and then the pseudo header is added
to that to derive the checksum for validation.
3) In both __skb_checksum_complete_header and __skb_checksum_complete,
set skb->csum_valid to whether checksum of zero was computed. This
allows skb_csum_unnecessary to return true without changing to
CHECKSUM_UNNECESSARY which was done previously.
4) Copy new csum related bits in __copy_skb_header.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Tom Herbert [Sun, 15 Jun 2014 06:23:52 +0000 (23:23 -0700)]
net: Fix GSO constants to match NETIF flags
Joseph Gasparakis reported that VXLAN GSO offload stopped working with
i40e device after recent UDP changes. The problem is that the
SKB_GSO_* bits are out of sync with the corresponding NETIF flags. This
patch fixes that. Also, we add BUILD_BUG_ONs in net_gso_ok for several
GSO constants that were missing to avoid the problem in the future.
Reported-by: Joseph Gasparakis <joseph.gasparakis@intel.com> Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Linus Torvalds [Sun, 15 Jun 2014 00:49:48 +0000 (19:49 -0500)]
Merge tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull more SCSI updates from James Bottomley:
"This is just a couple of drivers (hpsa and lpfc) that got left out for
further testing in linux-next. We also have one fix to a prior
submission (qla2xxx sparse)"
* tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (36 commits)
qla2xxx: fix sparse warnings introduced by previous target mode t10-dif patch
lpfc: Update lpfc version to driver version 10.2.8001.0
lpfc: Fix ExpressLane priority setup
lpfc: mark old devices as obsolete
lpfc: Fix for initializing RRQ bitmap
lpfc: Fix for cleaning up stale ring flag and sp_queue_event entries
lpfc: Update lpfc version to driver version 10.2.8000.0
lpfc: Update Copyright on changed files from 8.3.45 patches
lpfc: Update Copyright on changed files
lpfc: Fixed locking for scsi task management commands
lpfc: Convert runtime references to old xlane cfg param to fof cfg param
lpfc: Fix FW dump using sysfs
lpfc: Fix SLI4 s abort loop to process all FCP rings and under ring_lock
lpfc: Fixed kernel panic in lpfc_abort_handler
lpfc: Fix locking for postbufq when freeing
lpfc: Fix locking for lpfc_hba_down_post
lpfc: Fix dynamic transitions of FirstBurst from on to off
hpsa: fix handling of hpsa_volume_offline return value
hpsa: return -ENOMEM not -1 on kzalloc failure in hpsa_get_device_id
hpsa: remove messages about volume status VPD inquiry page not supported
...
Linus Torvalds [Sun, 15 Jun 2014 00:48:43 +0000 (19:48 -0500)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull more btrfs updates from Chris Mason:
"This has a few fixes since our last pull and a new ioctl for doing
btree searches from userland. It's very similar to the existing
ioctl, but lets us return larger items back down to the app"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: fix error handling in create_pending_snapshot
btrfs: fix use of uninit "ret" in end_extent_writepage()
btrfs: free ulist in qgroup_shared_accounting() error path
Btrfs: fix qgroups sanity test crash or hang
btrfs: prevent RCU warning when dereferencing radix tree slot
Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting
btrfs: new ioctl TREE_SEARCH_V2
btrfs: tree_search, search_ioctl: direct copy to userspace
btrfs: new function read_extent_buffer_to_user
btrfs: tree_search, copy_to_sk: return needed size on EOVERFLOW
btrfs: tree_search, copy_to_sk: return EOVERFLOW for too small buffer
btrfs: tree_search, search_ioctl: accept varying buffer
btrfs: tree_search: eliminate redundant nr_items check
Al Viro [Sat, 14 Jun 2014 06:12:41 +0000 (07:12 +0100)]
fix __swap_writepage() compile failure on old gcc versions
Tetsuo Handa wrote:
"Commit 62a8067a7f35 ("bio_vec-backed iov_iter") introduced an unnamed
union inside a struct which gcc-4.4.7 cannot handle. Name the unnamed
union as u in order to fix build failure"
Let's do this instead: there is only one place in the entire tree that
steps into this breakage. Anon structs and unions work in older gcc
versions; as the matter of fact, we have those in the tree - see e.g.
struct ieee80211_tx_info in include/net/mac80211.h
What doesn't work is handling their initializers:
struct {
int a;
union {
int b;
char c;
};
} x[2] = {{.a = 1, .c = 'a'}, {.a = 0, .b = 1}};
is the obvious syntax for initializer, perfectly fine for C11 and
handled correctly by gcc-4.7 or later.
Earlier versions, though, break on it - declaration is fine and so's
access to fields (i.e. x[0].c = 'a'; would produce the right code), but
members of the anon structs and unions are not inserted into the right
namespace. Tellingly, those older versions will not barf on struct {int
a; struct {int a;};}; - looks like they just have it hacked up somewhere
around the handling of . and -> instead of doing the right thing.
The easiest way to deal with that crap is to turn initialization of
those fields (in the only place where we have such initializer of
iov_iter) into plain assignment.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Sat, 14 Jun 2014 21:51:25 +0000 (14:51 -0700)]
Merge tag 'hsi-for-3.16-fixes1' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-hsi
Pull HSI build fixes from Sebastian Reichel:
- tighten dependency between ssi-protocol and omap-ssi to fix build
failures with randconfig.
- use normal module refcounting in omap driver to fix build with
disabled module support
* tag 'hsi-for-3.16-fixes1' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-hsi:
hsi: omap_ssi_port: use normal module refcounting
HSI: fix omap ssi driver dependency
Linus Torvalds [Sat, 14 Jun 2014 21:46:29 +0000 (14:46 -0700)]
Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 vdso fixes from Peter Anvin:
"Fixes for x86/vdso.
One is a simple build fix for bigendian hosts, one is to make "make
vdso_install" work again, and the rest is about working around a bug
in Google's Go language -- two are documentation patches that improves
the sample code that the Go coders took, modified, and broke; the
other two implements a workaround that keeps existing Go binaries from
segfaulting at least"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Fix vdso_install
x86/vdso: Hack to keep 64-bit Go programs working
x86/vdso: Add PUT_LE to store little-endian values
x86/vdso/doc: Make vDSO examples more portable
x86/vdso/doc: Rename vdso_test.c to vdso_standalone_test_x86.c
x86, vdso: Remove one final use of htole16()
Linus Torvalds [Sat, 14 Jun 2014 21:43:23 +0000 (14:43 -0700)]
Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon updates from Guenter Roeck:
- new driver for Sensirion SHTC1 humidity / temperature sensor
- convert ltc4151 and vexpress drivers to use devm functions
- drop generic chip detection from lm85 driver
- avoid forward declarations in atxp1 driver
- fix sign extensions in ina2xx driver
* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: vexpress: Use devm helper for hwmon device registration
hwmon: (atxp1) Avoid forward declaration
hwmon: add support for Sensirion SHTC1 sensor
hwmon: (ltc4151) Convert to devm_hwmon_device_register_with_groups
hwmon: (lm85) Drop generic detection
hwmon: (ina2xx) Cast to s16 on shunt and current regs
Eric Dumazet [Thu, 12 Jun 2014 23:13:06 +0000 (16:13 -0700)]
udp: ipv4: do not waste time in __udp4_lib_mcast_demux_lookup
Its too easy to add thousand of UDP sockets on a particular bucket,
and slow down an innocent multicast receiver.
Early demux is supposed to be an optimization, we should avoid spending
too much time in it.
It is interesting to note __udp4_lib_demux_lookup() only tries to
match first socket in the chain.
10 is the threshold we already have in __udp4_lib_lookup() to switch
to secondary hash.
Fixes: 421b3885bf6d5 ("udp: ipv4: Add udp early demux") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: David Held <drheld@google.com> Cc: Shawn Bohrer <sbohrer@rgmadvisors.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Cong Wang [Thu, 12 Jun 2014 18:53:10 +0000 (11:53 -0700)]
vxlan: use dev->needed_headroom instead of dev->hard_header_len
When we mirror packets from a vxlan tunnel to other device,
the mirror device should see the same packets (that is, without
outer header). Because vxlan tunnel sets dev->hard_header_len,
tcf_mirred() resets mac header back to outer mac, the mirror device
actually sees packets with outer headers
Vxlan tunnel should set dev->needed_headroom instead of
dev->hard_header_len, like what other ip tunnels do. This fixes
the above problem.
Cc: "David S. Miller" <davem@davemloft.net> Cc: stephen hemminger <stephen@networkplumber.org> Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Andy Lutomirski [Thu, 12 Jun 2014 15:28:10 +0000 (08:28 -0700)]
x86/vdso: Fix vdso_install
"make vdso_install" installs unstripped versions of the vdso objects
for the benefit of the debugger. This was broken by checkin:
6f121e548f83 x86, vdso: Reimplement vdso.so preparation in build-time C
The filenames are different now, so update the Makefile to cope.
This still installs the 64-bit vdso as vdso64.so. We believe this
will be okay, as the only known user is a patched gdb which is known
to use build-ids, but if it turns out to be a problem we may have to
add a link.
Dan McLeran [Fri, 6 Jun 2014 14:27:27 +0000 (08:27 -0600)]
NVMe: Fix START_STOP_UNIT Scsi->NVMe translation.
This patch contains several fixes for Scsi START_STOP_UNIT. The previous
code did not account for signed vs. unsigned arithmetic which resulted
in an invalid lowest power state caculation when the device only supports
1 power state.
The code for Power Condition == 2 (Idle) was not following the spec. The
spec calls for setting the device to specific power states, depending
upon Power Condition Modifier, without accounting for the number of
power states supported by the device.
The code for Power Condition == 3 (Standby) was using a hard-coded '0'
which is replaced with the macro POWER_STATE_0.
Signed-off-by: Dan McLeran <daniel.mcleran@intel.com> Reviewed-by: Vishal Verma <vishal.l.verma@linux.intel.com> Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Eric Sandeen [Thu, 12 Jun 2014 05:53:44 +0000 (00:53 -0500)]
btrfs: fix error handling in create_pending_snapshot
fcebe456 cut and pasted some code to a later point
in create_pending_snapshot(), but didn't switch
to the appropriate error handling for this stage
of the function.
Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
Eric Sandeen [Thu, 12 Jun 2014 05:39:58 +0000 (00:39 -0500)]
btrfs: fix use of uninit "ret" in end_extent_writepage()
If this condition in end_extent_writepage() is false:
if (tree->ops && tree->ops->writepage_end_io_hook)
we will then test an uninitialized "ret" at:
ret = ret < 0 ? ret : -EIO;
The test for ret is for the case where ->writepage_end_io_hook
failed, and we'd choose that ret as the error; but if
there is no ->writepage_end_io_hook, nothing sets ret.
Initializing ret to 0 should be sufficient; if
writepage_end_io_hook wasn't set, (!uptodate) means
non-zero err was passed in, so we choose -EIO in that case.
Signed-of-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Chris Mason <clm@fb.com>
projects / linux-beck.git / log