KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva_range()
When we invalidate a THP page, we call the handler with the same
rmap_pde argument 512 times in the following loop:
for each guest page in the range
for each level
unmap using rmap
This patch avoids these extra handler calls by changing the loop order
like this:
for each level
for each rmap in the range
unmap using rmap
With the preceding patches in the patch series, this made THP page
invalidation more than 5 times faster on our x86 host: the host became
more responsive during swapping the guest's memory as a result.
KVM: Separate rmap_pde from kvm_lpage_info->write_count
This makes it possible to loop over rmap_pde arrays in the same way as
we do over rmap so that we can optimize kvm_handle_hva_range() easily in
the following patch.
KVM: MMU: Make kvm_handle_hva() handle range of addresses
When guest's memory is backed by THP pages, MMU notifier needs to call
kvm_unmap_hva(), which in turn leads to kvm_handle_hva(), in a loop to
invalidate a range of pages which constitute one huge page:
for each page
for each memslot
if page is in memslot
unmap using rmap
This means although every page in that range is expected to be found in
the same memslot, we are forced to check unrelated memslots many times.
If the guest has more memslots, the situation will become worse.
Furthermore, if the range does not include any pages in the guest's
memory, the loop over the pages will just consume extra time.
This patch, together with the following patches, solves this problem by
introducing kvm_handle_hva_range() which makes the loop look like this:
for each memslot
for each page in memslot
unmap using rmap
In this new processing, the actual work is converted to a loop over rmap
which is much more cache friendly than before.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Alexander Graf <agraf@suse.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
KVM: Introduce hva_to_gfn_memslot() for kvm_handle_hva()
This restricts hva handling in mmu code and makes it easier to extend
kvm_handle_hva() so that it can treat a range of addresses later in this
patch series.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Cc: Alexander Graf <agraf@suse.de> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This reverts commit f9808b7fd422b965cea52e05ba470e0a473c53d3.
After commit 'kvm: switch to apic_set_eoi_write, apic_write'
the stubs are no longer needed as kvm does not look at apicdrivers anymore.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
KVM PV EOI optimization overrides eoi_write apic op with its own
version. Add an API for this to avoid meddling with core x86 apic driver
data structures directly.
For KVM use, we don't need any guarantees about when the switch to the
new op will take place, so it could in theory use this API after SMP init,
but it currently doesn't, and restricting callers to early init makes it
clear that it's safe as it won't race with actual APIC driver use.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Sun, 15 Jul 2012 09:41:47 +0000 (12:41 +0300)]
Merge branch 'for-upstream' of git://github.com/agraf/linux-2.6 into next
ppc queue from Alex Graf:
* Prepare some of the booke code for 64 bit support
* BookE: Fix ESR flag in DSI
* BookE: Add rfci emulation
* 'for-upstream' of git://github.com/agraf/linux-2.6:
KVM: PPC: Critical interrupt emulation support
KVM: PPC: e500mc: Fix tlbilx emulation for 64-bit guests
KVM: PPC64: booke: Set interrupt computation mode for 64-bit host
KVM: PPC: bookehv: Add ESR flag to Data Storage Interrupt
KVM: PPC: bookehv64: Add support for std/ld emulation.
booke: Added crit/mc exception handler for e500v2
booke/bookehv: Add host crit-watchdog exception support
KVM: VMX: Implement PCID/INVPCID for guests with EPT
This patch handles PCID/INVPCID for guests.
Process-context identifiers (PCIDs) are a facility by which a logical processor
may cache information for multiple linear-address spaces so that the processor
may retain cached information when software switches to a different linear
address space. Refer to section 4.10.1 in IA32 Intel Software Developer's Manual
Volume 3A for details.
For guests with EPT, the PCID feature is enabled and INVPCID behaves as running
natively.
For guests without EPT, the PCID feature is disabled and INVPCID triggers #UD.
Signed-off-by: Junjie Mao <junjie.mao@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: Add x86_hyper_kvm to complete detect_hypervisor_platform check
While debugging I noticed that unlike all the other hypervisor code in the
kernel, kvm does not have an entry for x86_hyper which is used in
detect_hypervisor_platform() which results in a nice printk in the
syslog. This is only really a stub function but it
does make kvm more consistent with the other hypervisors.
Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Avi Kivity <avi@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marcelo Tostatti <mtosatti@redhat.com> Cc: kvm@vger.kernel.org Signed-off-by: Avi Kivity <avi@redhat.com>
Xiao Guangrong [Wed, 20 Jun 2012 07:59:18 +0000 (15:59 +0800)]
KVM: MMU: fast path of handling guest page fault
If the the present bit of page fault error code is set, it indicates
the shadow page is populated on all levels, it means what we do is
only modify the access bit which can be done out of mmu-lock
Currently, in order to simplify the code, we only fix the page fault
caused by write-protect on the fast path
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Xiao Guangrong [Wed, 20 Jun 2012 07:58:58 +0000 (15:58 +0800)]
KVM: MMU: introduce SPTE_MMU_WRITEABLE bit
This bit indicates whether the spte can be writable on MMU, that means
the corresponding gpte is writable and the corresponding gfn is not
protected by shadow page protection
In the later path, SPTE_MMU_WRITEABLE will indicates whether the spte
can be locklessly updated
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Tue, 12 Jun 2012 17:30:18 +0000 (20:30 +0300)]
KVM: VMX: Emulate invalid guest state by default
Our emulation should be complete enough that we can emulate guests
while they are in big real mode, or in a mode transition that is not
virtualizable without unrestricted guest support.
Avi Kivity [Wed, 13 Jun 2012 13:30:53 +0000 (16:30 +0300)]
KVM: x86 emulator: make loading TR set the busy bit
Guest software doesn't actually depend on it, but vmx will refuse us
entry if we don't. Set the bit in both the cached segment and memory,
just to be nice.
Avi Kivity [Tue, 12 Jun 2012 17:03:23 +0000 (20:03 +0300)]
KVM: x86 emulator: implement ENTER
Opcode C8.
Only ENTER with lexical nesting depth 0 is implemented, since others are
very rare. We'll fail emulation if nonzero lexical depth is used so data
is not corrupted.
Avi Kivity [Mon, 11 Jun 2012 16:40:15 +0000 (19:40 +0300)]
KVM: x86 emulator: fix byte-sized MOVZX/MOVSX
Commit 2adb5ad9fe1 removed ByteOp from MOVZX/MOVSX, replacing them by
SrcMem8, but neglected to fix the dependency in the emulation code
on ByteOp. This caused the instruction not to have any effect in
some circumstances.
Fix by replacing the check for ByteOp with the equivalent src.op_bytes == 1.
Avi Kivity [Sun, 10 Jun 2012 15:07:57 +0000 (18:07 +0300)]
KVM: VMX: Fix interrupt exit condition during emulation
Checking EFLAGS.IF is incorrect as we might be in interrupt shadow. If
that is the case, the main loop will notice that and not inject the interrupt,
causing an endless loop.
Fix by using vmx_interrupt_allowed() to check if we can inject an interrupt
instead.
Avi Kivity [Sun, 10 Jun 2012 14:11:00 +0000 (17:11 +0300)]
KVM: x86 emulator: initialize memop
memop is not initialized; this can lead to a two-byte operation
following a 4-byte operation to see garbage values. Usually
truncation fixes things fot us later on, but at least in one case
(call abs) it doesn't.
Fix by moving memop to the auto-initialized field area.
Avi Kivity [Thu, 7 Jun 2012 14:06:10 +0000 (17:06 +0300)]
KVM: VMX: Relax check on unusable segment
Some userspace (e.g. QEMU 1.1) munge the d and g bits of segment
descriptors, causing us not to recognize them as unusable segments
with emulate_invalid_guest_state=1. Relax the check by testing for
segment not present (a non-present segment cannot be usable).
Avi Kivity [Thu, 7 Jun 2012 11:11:36 +0000 (14:11 +0300)]
KVM: x86 emulator: emulate cpuid
Opcode 0F A2.
Used by Linux during the mode change trampoline while in a state that is
not virtualizable on vmx without unrestricted_guest, so we need to emulate
it is emulate_invalid_guest_state=1.
Avi Kivity [Thu, 7 Jun 2012 11:10:16 +0000 (14:10 +0300)]
KVM: x86 emulator: change ->get_cpuid() accessor to use the x86 semantics
Instead of getting an exact leaf, follow the spec and fall back to the last
main leaf instead. This lets us easily emulate the cpuid instruction in the
emulator.
Avi Kivity [Thu, 7 Jun 2012 11:07:48 +0000 (14:07 +0300)]
KVM: Split cpuid register access from computation
Introduce kvm_cpuid() to perform the leaf limit check and calculate
register values, and let kvm_emulate_cpuid() just handle reading and
writing the registers from/to the vcpu. This allows us to reuse
kvm_cpuid() in a context where directly reading and writing registers
is not desired.
Avi Kivity [Wed, 6 Jun 2012 15:36:48 +0000 (18:36 +0300)]
KVM: VMX: Return correct CPL during transition to protected mode
In protected mode, the CPL is defined as the lower two bits of CS, as set by
the last far jump. But during the transition to protected mode, there is no
last far jump, so we need to return zero (the inherited real mode CPL).
Fix by reading CPL from the cache during the transition. This isn't 100%
correct since we don't set the CPL cache on a far jump, but since protected
mode transition will always jump to a segment with RPL=0, it will always
work.
Avi Kivity [Sun, 8 Jul 2012 14:16:30 +0000 (17:16 +0300)]
KVM: MMU: Force cr3 reload with two dimensional paging on mov cr3 emulation
Currently the MMU's ->new_cr3() callback does nothing when guest paging
is disabled or when two-dimentional paging (e.g. EPT on Intel) is active.
This means that an emulated write to cr3 can be lost; kvm_set_cr3() will
write vcpu-arch.cr3, but the GUEST_CR3 field in the VMCS will retain its
old value and this is what the guest sees.
This bug did not have any effect until now because:
- with unrestricted guest, or with svm, we never emulate a mov cr3 instruction
- without unrestricted guest, and with paging enabled, we also never emulate a
mov cr3 instruction
- without unrestricted guest, but with paging disabled, the guest's cr3 is
ignored until the guest enables paging; at this point the value from arch.cr3
is loaded correctly my the mov cr0 instruction which turns on paging
However, the patchset that enables big real mode causes us to emulate mov cr3
instructions in protected mode sometimes (when guest state is not virtualizable
by vmx); this mov cr3 is effectively ignored and will crash the guest.
The fix is to make nonpaging_new_cr3() call mmu_free_roots() to force a cr3
reload. This is awkward because now all the new_cr3 callbacks to the same
thing, and because mmu_free_roots() is somewhat of an overkill; but fixing
that is more complicated and will be done after this minimal fix.
Observed in the Window XP 32-bit installer while bringing up secondary vcpus.
Rik van Riel [Tue, 19 Jun 2012 20:51:04 +0000 (16:51 -0400)]
KVM: handle last_boosted_vcpu = 0 case
If last_boosted_vcpu == 0, then we fall through all test cases and
may end up with all VCPUs pouncing on vcpu 0. With a large enough
guest, this can result in enormous runqueue lock contention, which
can prevent vcpu0 from running, leading to a livelock.
Changing < to <= makes sure we properly handle that case.
Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Heiko Carstens [Tue, 26 Jun 2012 14:06:39 +0000 (16:06 +0200)]
KVM: s390: fix sigp set prefix status stored cases
If an invalid parameter is passed or the addressed cpu is in an
incorrect state sigp set prefix will store a status.
This status must only have bits set as defined by the architecture.
The current kvm implementation missed to clear bits and also did
not set the intended status bit ("and" instead of "or" operation).
Heiko Carstens [Tue, 26 Jun 2012 14:06:38 +0000 (16:06 +0200)]
KVM: s390: fix sigp sense running condition code handling
Only if the sensed cpu is not running a status is stored, which
is reflected by condition code 1. If the cpu is running, condition
code 0 should be returned.
Just the opposite of what the code is doing.
Heiko Carstens [Tue, 26 Jun 2012 14:06:37 +0000 (16:06 +0200)]
s390/smp/kvm: unifiy sigp definitions
The smp and the kvm code have different defines for the sigp order codes.
Let's just have a single place where these are defined.
Also move the sigp condition code and sigp cpu status bits to the new
sigp.h header file.
Heiko Carstens [Tue, 26 Jun 2012 14:06:36 +0000 (16:06 +0200)]
s390/smp: remove redundant check
condition code "status stored" for sigp sense running always implies
that only the "not running" status bit is set. Therefore no need to
check if it is set.
Marc Zyngier [Fri, 15 Jun 2012 19:07:24 +0000 (15:07 -0400)]
KVM: Guard mmu_notifier specific code with CONFIG_MMU_NOTIFIER
In order to avoid compilation failure when KVM is not compiled in,
guard the mmu_notifier specific sections with both CONFIG_MMU_NOTIFIER
and KVM_ARCH_WANT_MMU_NOTIFIER, like it is being done in the rest of
the KVM code.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
On UP i386, when APIC is disabled
# CONFIG_X86_UP_APIC is not set
# CONFIG_PCI_IOAPIC is not set
code looking at apicdrivers never has any effect but it
still gets compiled in. In particular, this causes
build failures with kvm, but it generally bloats the kernel
unnecessarily.
Fix by defining both __apicdrivers and __apicdrivers_end
to be NULL when CONFIG_X86_LOCAL_APIC is unset: I verified
that as the result any loop scanning __apicdrivers gets optimized out by
the compiler.
Warning: a .config with apic disabled doesn't seem to boot
for me (even without this patch). Still verifying why,
meanwhile this patch is compile-tested only.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reported-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Implementation of PV EOI using shared memory.
This reduces the number of exits an interrupt
causes as much as by half.
The idea is simple: there's a bit, per APIC, in guest memory,
that tells the guest that it does not need EOI.
We set it before injecting an interrupt and clear
before injecting a nested one. Guest tests it using
a test and clear operation - this is necessary
so that host can detect interrupt nesting -
and if set, it can skip the EOI MSR.
There's a new MSR to set the address of said register
in guest memory. Otherwise not much changed:
- Guest EOI is not required
- Register is tested & ISR is automatically cleared on exit
For testing results see description of previous patch
'kvm_para: guest side for eoi avoidance'.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Each time we need to cancel injection we invoke same code
(cancel_injection callback). Move it towards the end of function using
the familiar goto on error pattern.
Will make it easier to do more cleanups for PV EOI.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Commit eb0dc6d0368072236dcd086d7fdc17fd3c4574d4 introduced apic
attention bitmask but kvm still syncs lapic unconditionally.
As that commit suggested and in anticipation of adding more attention
bits, only sync lapic if(apic_attention).
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
x86, bitops: note on __test_and_clear_bit atomicity
__test_and_clear_bit is actually atomic with respect
to the local CPU. Add a note saying that KVM on x86
relies on this behaviour so people don't accidentaly break it.
Also warn not to rely on this in portable code.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
The idea is simple: there's a bit, per APIC, in guest memory,
that tells the guest that it does not need EOI.
Guest tests it using a single est and clear operation - this is
necessary so that host can detect interrupt nesting - and if set, it can
skip the EOI MSR.
I run a simple microbenchmark to show exit reduction
(note: for testing, need to apply follow-up patch
'kvm: host side for eoi optimization' + a qemu patch
I posted separately, on host):
We perform ISR lookups twice: during interrupt
injection and on EOI. Typical workloads only have
a single bit set there. So we can avoid ISR scans by
1. counting bits as we set/clear them in ISR
2. on set, caching the injected vector number
3. on clear, invalidating the cache
The real purpose of this is enabling PV EOI
which needs to quickly validate the vector.
But non PV guests also benefit: with this patch,
and without interrupt nesting, apic_find_highest_isr
will always return immediately without scanning ISR.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Christoffer Dall [Fri, 15 Jun 2012 19:07:13 +0000 (15:07 -0400)]
KVM: Introduce __KVM_HAVE_IRQ_LINE
This is a preparatory patch for the KVM/ARM implementation. KVM/ARM will use
the KVM_IRQ_LINE ioctl, which is currently conditional on
__KVM_HAVE_IOAPIC, but ARM obviously doesn't have any IOAPIC support and we
need a separate define.
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Marc Zyngier [Fri, 15 Jun 2012 19:07:02 +0000 (15:07 -0400)]
KVM: use KVM_CAP_IRQ_ROUTING to protect the routing related code
The KVM code sometimes uses CONFIG_HAVE_KVM_IRQCHIP to protect
code that is related to IRQ routing, which not all in-kernel
irqchips may support.
Use KVM_CAP_IRQ_ROUTING instead.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com> Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: s390: Set CPU in stopped state on initial cpu reset
The initial cpu reset sets the cpu in the stopped state.
Several places check for the cpu state (e.g. sigp set prefix) and
not setting the STOPPED state triggered errors with newer guest
kernels after reboot.
Avi Kivity [Wed, 6 Jun 2012 12:31:34 +0000 (15:31 +0300)]
Merge branch 'for-upstream' of git://github.com/agraf/linux-2.6 into next
Alex says:
"Changes this time include:
- Generalize KVM_GUEST support to overall ePAPR code
- Fix reset for Book3S HV
- Fix machine check deferral when CONFIG_KVM_GUEST=y
- Add support for BookE register DECAR"
* 'for-upstream' of git://github.com/agraf/linux-2.6:
KVM: PPC: Not optimizing MSR_CE and MSR_ME with paravirt.
KVM: PPC: booke: Added DECAR support
KVM: PPC: Book3S HV: Make the guest hash table size configurable
KVM: PPC: Factor out guest epapr initialization
static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long data)
{
- u64 *spte;
+ u64 *sptep;
+ struct rmap_iterator iter; <- line 1271
int young = 0;
/*
The reason I think is that the compiler assumes that
the rmap value could be 0, so
static u64 *rmap_get_first(unsigned long rmap, struct rmap_iterator
*iter)
{
if (!rmap)
return NULL;
Orit Wasserman [Thu, 31 May 2012 11:49:22 +0000 (14:49 +0300)]
KVM: VMX: Fix KVM_SET_SREGS with big real mode segments
For example migration between Westmere and Nehelem hosts, caught in big real mode.
The code that fixes the segments for real mode guest was moved from enter_rmode
to vmx_set_segments. enter_rmode calls vmx_set_segments for each segment.
Signed-off-by: Orit Wasserman <owasserm@rehdat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Gleb Natapov [Mon, 4 Jun 2012 11:53:23 +0000 (14:53 +0300)]
KVM: MMU: do not iterate over all VMs in mmu_shrink()
mmu_shrink() needlessly iterates over all VMs even though it will not
attempt to free mmu pages from more than one on them. Fix that and also
check used mmu pages count outside of VM lock to skip inactive VMs faster.
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Thu, 17 May 2012 10:14:08 +0000 (13:14 +0300)]
KVM: ia64: Mark ia64 KVM as BROKEN
Practically all patches to ia64 KVM are build fixes; numerous warnings remain;
the last patch from the maintainer was committed more than three years ago. It
is clear that no one is using this thing.
Mark as BROKEN to ensure people don't get hit by pointless build problems.
Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
projects / linux-beck.git / log