Paul Mackerras [Wed, 29 Jun 2011 00:19:22 +0000 (00:19 +0000)]
KVM: PPC: Pass init/destroy vm and prepare/commit memory region ops down
This arranges for the top-level arch/powerpc/kvm/powerpc.c file to
pass down some of the calls it gets to the lower-level subarchitecture
specific code. The lower-level implementations (in booke.c and book3s.c)
are no-ops. The coming book3s_hv.c will need this.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Paul Mackerras [Wed, 29 Jun 2011 00:18:52 +0000 (00:18 +0000)]
KVM: PPC: Deliver program interrupts right away instead of queueing them
Doing so means that we don't have to save the flags anywhere and gets
rid of the last reference to to_book3s(vcpu) in arch/powerpc/kvm/book3s.c.
Doing so is OK because a program interrupt won't be generated at the
same time as any other synchronous interrupt. If a program interrupt
and an asynchronous interrupt (external or decrementer) are generated
at the same time, the program interrupt will be delivered, which is
correct because it has a higher priority, and then the asynchronous
interrupt will be masked.
We don't ever generate system reset or machine check interrupts to the
guest, but if we did, then we would need to make sure they got delivered
rather than the program interrupt. The current code would be wrong in
this situation anyway since it would deliver the program interrupt as
well as the reset/machine check interrupt.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Paul Mackerras [Wed, 29 Jun 2011 00:18:26 +0000 (00:18 +0000)]
powerpc, KVM: Rework KVM checks in first-level interrupt handlers
Instead of branching out-of-line with the DO_KVM macro to check if we
are in a KVM guest at the time of an interrupt, this moves the KVM
check inline in the first-level interrupt handlers. This speeds up
the non-KVM case and makes sure that none of the interrupt handlers
are missing the check.
Because the first-level interrupt handlers are now larger, some things
had to be move out of line in exceptions-64s.S.
This all necessitated some minor changes to the interrupt entry code
in KVM. This also streamlines the book3s_32 KVM test.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Paul Mackerras [Wed, 29 Jun 2011 00:17:58 +0000 (00:17 +0000)]
KVM: PPC: Split out code from book3s.c into book3s_pr.c
In preparation for adding code to enable KVM to use hypervisor mode
on 64-bit Book 3S processors, this splits book3s.c into two files,
book3s.c and book3s_pr.c, where book3s_pr.c contains the code that is
specific to running the guest in problem state (user mode) and book3s.c
contains code which should apply to all Book 3S processors.
In doing this, we abstract some details, namely the interrupt offset,
updating the interrupt pending flag, and detecting if the guest is
in a critical section. These are all things that will be different
when we use hypervisor mode.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Paul Mackerras [Wed, 29 Jun 2011 00:17:33 +0000 (00:17 +0000)]
KVM: PPC: Move fields between struct kvm_vcpu_arch and kvmppc_vcpu_book3s
This moves the slb field, which represents the state of the emulated
SLB, from the kvmppc_vcpu_book3s struct to the kvm_vcpu_arch, and the
hpte_hash_[v]pte[_long] fields from kvm_vcpu_arch to kvmppc_vcpu_book3s.
This is in accord with the principle that the kvm_vcpu_arch struct
represents the state of the emulated CPU, and the kvmppc_vcpu_book3s
struct holds the auxiliary data structures used in the emulation.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Paul Mackerras [Wed, 29 Jun 2011 00:16:42 +0000 (00:16 +0000)]
KVM: PPC: Fix machine checks on 32-bit Book3S
Commit 69acc0d3ba ("KVM: PPC: Resolve real-mode handlers through
function exports") resulted in vcpu->arch.trampoline_lowmem and
vcpu->arch.trampoline_enter ending up with kernel virtual addresses
rather than physical addresses. This is OK on 64-bit Book3S machines,
which ignore the top 4 bits of the effective address in real mode,
but on 32-bit Book3S machines, accessing these addresses in real mode
causes machine check interrupts, as the hardware uses the whole
effective address as the physical address in real mode.
This fixes the problem by using __pa() to convert these addresses
to physical addresses.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Liu Yu [Tue, 14 Jun 2011 23:35:14 +0000 (18:35 -0500)]
KVM: PPC: e500: Add shadow PID support
Dynamically assign host PIDs to guest PIDs, splitting each guest PID into
multiple host (shadow) PIDs based on kernel/user and MSR[IS/DS]. Use
both PID0 and PID1 so that the shadow PIDs for the right mode can be
selected, that correspond both to guest TID = zero and guest TID = guest
PID.
This allows us to significantly reduce the frequency of needing to
invalidate the entire TLB. When the guest mode or PID changes, we just
update the host PID0/PID1. And since the allocation of shadow PIDs is
global, multiple guests can share the TLB without conflict.
Note that KVM does not yet support the guest setting PID1 or PID2 to
a value other than zero. This will need to be fixed for nested KVM
to work. Until then, we enforce the requirement for guest PID1/PID2
to stay zero by failing the emulation if the guest tries to set them
to something else.
Signed-off-by: Liu Yu <yu.liu@freescale.com> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:41 +0000 (18:34 -0500)]
KVM: PPC: e500: enable magic page
This is a shared page used for paravirtualization. It is always present
in the guest kernel's effective address space at the address indicated
by the hypercall that enables it.
The physical address specified by the hypercall is not used, as
e500 does not have real mode.
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:39 +0000 (18:34 -0500)]
KVM: PPC: e500: Support large page mappings of PFNMAP vmas.
This allows large pages to be used on guest mappings backed by things like
/dev/mem, resulting in a significant speedup when guest memory
is mapped this way (it's useful for directly-assigned MMIO, too).
This is not a substitute for hugetlbfs integration, but is useful for
configurations where devices are directly assigned on chips without an
IOMMU -- in these cases, we need guest physical and true physical to
match, and be contiguous, so static reservation and mapping via /dev/mem
is the most straightforward way to set things up.
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:37 +0000 (18:34 -0500)]
KVM: PPC: e500: Eliminate shadow_pages[], and use pfns instead.
This is in line with what other architectures do, and will allow us to
map things other than ordinary, unreserved kernel pages -- such as
dedicated devices, or large contiguous reserved regions.
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:35 +0000 (18:34 -0500)]
KVM: PPC: e500: don't use MAS0 as intermediate storage.
This avoids races. It also means that we use the shadow TLB way,
rather than the hardware hint -- if this is a problem, we could do
a tlbsx before inserting a TLB0 entry.
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:31 +0000 (18:34 -0500)]
KVM: PPC: e500: Save/restore SPE state
This is done lazily. The SPE save will be done only if the guest has
used SPE since the last preemption or heavyweight exit. Restore will be
done only on demand, when enabling MSR_SPE in the shadow MSR, in response
to an SPE fault or mtmsr emulation.
For SPEFSCR, Linux already switches it on context switch (non-lazily), so
the only remaining bit is to save it between qemu and the guest.
Signed-off-by: Liu Yu <yu.liu@freescale.com> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:29 +0000 (18:34 -0500)]
KVM: PPC: booke: use shadow_msr
Keep the guest MSR and the guest-mode true MSR separate, rather than
modifying the guest MSR on each guest entry to produce a true MSR.
Any bits which should be modified based on guest MSR must be explicitly
propagated from vcpu->arch.shared->msr to vcpu->arch.shadow_msr in
kvmppc_set_msr().
While we're modifying the guest entry code, reorder a few instructions
to bury some load latencies.
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Scott Wood [Tue, 14 Jun 2011 23:34:27 +0000 (18:34 -0500)]
powerpc/e500: SPE register saving: take arbitrary struct offset
Previously, these macros hardcoded THREAD_EVR0 as the base of the save
area, relative to the base register passed. This base offset is now
passed as a separate macro parameter, allowing reuse with other SPE
save areas, such as used by KVM.
Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
yu liu [Tue, 14 Jun 2011 23:34:25 +0000 (18:34 -0500)]
powerpc/e500: Save SPEFCSR in flush_spe_to_thread()
giveup_spe() saves the SPE state which is protected by MSR[SPE].
However, modifying SPEFSCR does not trap when MSR[SPE]=0.
And since SPEFSCR is already saved/restored in _switch(),
not all the callers want to save SPEFSCR again.
Thus, saving SPEFSCR should not belong to giveup_spe().
This patch moves SPEFSCR saving to flush_spe_to_thread(),
and cleans up the caller that needs to save SPEFSCR accordingly.
Signed-off-by: Liu Yu <yu.liu@freescale.com> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Alexander Graf [Tue, 7 Jun 2011 18:45:34 +0000 (20:45 +0200)]
KVM: PPC: Resolve real-mode handlers through function exports
Up until now, Book3S KVM had variables stored in the kernel that a kernel module
or the kvm code in the kernel could read from to figure out where some real mode
helper functions are located.
This is all unnecessary. The high bits of the EA get ignore in real mode, so we
can just use the pointer as is. Also, it's a lot easier on relocations when we
use the normal way of resolving the address to a function, instead of jumping
through hoops.
This patch fixes compilation with CONFIG_RELOCATABLE=y.
Stuart Yoder [Tue, 17 May 2011 23:26:00 +0000 (18:26 -0500)]
KVM: PPC: fix partial application of "exit timing in ticks"
When http://www.spinics.net/lists/kvm-ppc/msg02664.html
was applied to produce commit b51e7aa7ed6d8d134d02df78300ab0f91cfff4d2,
the removal of the conversion in add_exit_timing was left out.
Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Avi Kivity [Mon, 6 Jun 2011 13:11:54 +0000 (16:11 +0300)]
KVM: MMU: Adjust shadow paging to work when SMEP=1 and CR0.WP=0
When CR0.WP=0, we sometimes map user pages as kernel pages (to allow
the kernel to write to them). Unfortunately this also allows the kernel
to fetch from these pages, even if CR4.SMEP is set.
Adjust for this by also setting NX on the spte in these circumstances.
Andre Przywara [Fri, 10 Jun 2011 09:35:30 +0000 (11:35 +0200)]
KVM: fix XSAVE bit scanning (now properly)
commit 123108f1c1aafd51d6a5c79cc04d7999dd88a930 tried to fix KVMs
XSAVE valid feature scanning, but it was wrong. It was not considering
the sparse nature of this bitfield, instead reading values from
uninitialized members of the entries array.
This patch now separates subleaf indicies from KVM's array indicies
and fills the entry before querying it's value.
This fixes AVX support in KVM guests.
Signed-off-by: Andre Przywara <andre.przywara@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Alexander Graf [Wed, 8 Jun 2011 00:45:37 +0000 (02:45 +0200)]
KVM: Add compat ioctl for KVM_SET_SIGNAL_MASK
KVM has an ioctl to define which signal mask should be used while running
inside VCPU_RUN. At least for big endian systems, this mask is different
on 32-bit and 64-bit systems (though the size is identical).
Add a compat wrapper that converts the mask to whatever the kernel accepts,
allowing 32-bit kvm user space to set signal masks.
This patch fixes qemu with --enable-io-thread on ppc64 hosts when running
32-bit user land.
Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
Nadav Har'El [Thu, 2 Jun 2011 08:54:52 +0000 (11:54 +0300)]
KVM: nVMX: Fix bug preventing more than two levels of nesting
The nested VMX feature is supposed to fully emulate VMX for the guest. This
(theoretically) not only allows it to run its own guests, but also also
to further emulate VMX for its own guests, and allow arbitrarily deep nesting.
This patch fixes a bug (discovered by Kevin Tian) in handling a VMLAUNCH
by L2, which prevented deeper nesting.
Deeper nesting now works (I only actually tested L3), but is currently
*absurdly* slow, to the point of being unusable.
Takuya Yoshikawa [Sun, 29 May 2011 12:53:48 +0000 (21:53 +0900)]
KVM: x86 emulator: Use the pointers ctxt and c consistently
We should use the local variables ctxt and c when the emulate_ctxt and
decode appears many times. At least, we need to be consistent about
how we use these in a function.
Nadav Har'El [Wed, 25 May 2011 20:17:11 +0000 (23:17 +0300)]
KVM: nVMX: Documentation
This patch includes a brief introduction to the nested vmx feature in the
Documentation/kvm directory. The document also includes a copy of the
vmcs12 structure, as requested by Avi Kivity.
Nadav Har'El [Wed, 25 May 2011 20:16:10 +0000 (23:16 +0300)]
KVM: nVMX: Add VMX to list of supported cpuid features
If the "nested" module option is enabled, add the "VMX" CPU feature to the
list of CPU features KVM advertises with the KVM_GET_SUPPORTED_CPUID ioctl.
Qemu uses this ioctl, and intersects KVM's list with its own list of desired
cpu features (depending on the -cpu option given to qemu) to determine the
final list of features presented to the guest.
Nadav Har'El [Wed, 25 May 2011 20:15:39 +0000 (23:15 +0300)]
KVM: nVMX: Additional TSC-offset handling
In the unlikely case that L1 does not capture MSR_IA32_TSC, L0 needs to
emulate this MSR write by L2 by modifying vmcs02.tsc_offset. We also need to
set vmcs12.tsc_offset, for this change to survive the next nested entry (see
prepare_vmcs02()).
Additionally, we also need to modify vmx_adjust_tsc_offset: The semantics
of this function is that the TSC of all guests on this vcpu, L1 and possibly
several L2s, need to be adjusted. To do this, we need to adjust vmcs01's
tsc_offset (this offset will also apply to each L2s we enter). We can't set
vmcs01 now, so we have to remember this adjustment and apply it when we
later exit to L1.
Nadav Har'El [Wed, 25 May 2011 20:15:08 +0000 (23:15 +0300)]
KVM: nVMX: Further fixes for lazy FPU loading
KVM's "Lazy FPU loading" means that sometimes L0 needs to set CR0.TS, even
if a guest didn't set it. Moreover, L0 must also trap CR0.TS changes and
NM exceptions, even if we have a guest hypervisor (L1) who didn't want these
traps. And of course, conversely: If L1 wanted to trap these events, we
must let it, even if L0 is not interested in them.
This patch fixes some existing KVM code (in update_exception_bitmap(),
vmx_fpu_activate(), vmx_fpu_deactivate()) to do the correct merging of L0's
and L1's needs. Note that handle_cr() was already fixed in the above patch,
and that new code in introduced in previous patches already handles CR0
correctly (see prepare_vmcs02(), prepare_vmcs12(), and nested_vmx_vmexit()).
Nadav Har'El [Wed, 25 May 2011 20:14:38 +0000 (23:14 +0300)]
KVM: nVMX: Handling of CR0 and CR4 modifying instructions
When L2 tries to modify CR0 or CR4 (with mov or clts), and modifies a bit
which L1 asked to shadow (via CR[04]_GUEST_HOST_MASK), we already do the right
thing: we let L1 handle the trap (see nested_vmx_exit_handled_cr() in a
previous patch).
When L2 modifies bits that L1 doesn't care about, we let it think (via
CR[04]_READ_SHADOW) that it did these modifications, while only changing
(in GUEST_CR[04]) the bits that L0 doesn't shadow.
This is needed for corect handling of CR0.TS for lazy FPU loading: L0 may
want to leave TS on, while pretending to allow the guest to change it.
Nadav Har'El [Wed, 25 May 2011 20:14:07 +0000 (23:14 +0300)]
KVM: nVMX: Correct handling of idt vectoring info
This patch adds correct handling of IDT_VECTORING_INFO_FIELD for the nested
case.
When a guest exits while delivering an interrupt or exception, we get this
information in IDT_VECTORING_INFO_FIELD in the VMCS. When L2 exits to L1,
there's nothing we need to do, because L1 will see this field in vmcs12, and
handle it itself. However, when L2 exits and L0 handles the exit itself and
plans to return to L2, L0 must inject this event to L2.
In the normal non-nested case, the idt_vectoring_info case is discovered after
the exit, and the decision to inject (though not the injection itself) is made
at that point. However, in the nested case a decision of whether to return
to L2 or L1 also happens during the injection phase (see the previous
patches), so in the nested case we can only decide what to do about the
idt_vectoring_info right after the injection, i.e., in the beginning of
vmx_vcpu_run, which is the first time we know for sure if we're staying in
L2.
Therefore, when we exit L2 (is_guest_mode(vcpu)), we disable the regular
vmx_complete_interrupts() code which queues the idt_vectoring_info for
injection on next entry - because such injection would not be appropriate
if we will decide to exit to L1. Rather, we just save the idt_vectoring_info
and related fields in vmcs12 (which is a convenient place to save these
fields). On the next entry in vmx_vcpu_run (*after* the injection phase,
potentially exiting to L1 to inject an event requested by user space), if
we find ourselves in L1 we don't need to do anything with those values
we saved (as explained above). But if we find that we're in L2, or rather
*still* at L2 (it's not nested_run_pending, meaning that this is the first
round of L2 running after L1 having just launched it), we need to inject
the event saved in those fields - by writing the appropriate VMCS fields.
Nadav Har'El [Wed, 25 May 2011 20:13:06 +0000 (23:13 +0300)]
KVM: nVMX: Correct handling of interrupt injection
The code in this patch correctly emulates external-interrupt injection
while a nested guest L2 is running.
Because of this code's relative un-obviousness, I include here a longer-than-
usual justification for what it does - much longer than the code itself ;-)
To understand how to correctly emulate interrupt injection while L2 is
running, let's look first at what we need to emulate: How would things look
like if the extra L0 hypervisor layer is removed, and instead of L0 injecting
an interrupt, we had hardware delivering an interrupt?
Now we have L1 running on bare metal with a guest L2, and the hardware
generates an interrupt. Assuming that L1 set PIN_BASED_EXT_INTR_MASK to 1, and
VM_EXIT_ACK_INTR_ON_EXIT to 0 (we'll revisit these assumptions below), what
happens now is this: The processor exits from L2 to L1, with an external-
interrupt exit reason but without an interrupt vector. L1 runs, with
interrupts disabled, and it doesn't yet know what the interrupt was. Soon
after, it enables interrupts and only at that moment, it gets the interrupt
from the processor. when L1 is KVM, Linux handles this interrupt.
Now we need exactly the same thing to happen when that L1->L2 system runs
on top of L0, instead of real hardware. This is how we do this:
When L0 wants to inject an interrupt, it needs to exit from L2 to L1, with
external-interrupt exit reason (with an invalid interrupt vector), and run L1.
Just like in the bare metal case, it likely can't deliver the interrupt to
L1 now because L1 is running with interrupts disabled, in which case it turns
on the interrupt window when running L1 after the exit. L1 will soon enable
interrupts, and at that point L0 will gain control again and inject the
interrupt to L1.
Finally, there is an extra complication in the code: when nested_run_pending,
we cannot return to L1 now, and must launch L2. We need to remember the
interrupt we wanted to inject (and not clear it now), and do it on the
next exit.
The above explanation shows that the relative strangeness of the nested
interrupt injection code in this patch, and the extra interrupt-window
exit incurred, are in fact necessary for accurate emulation, and are not
just an unoptimized implementation.
Let's revisit now the two assumptions made above:
If L1 turns off PIN_BASED_EXT_INTR_MASK (no hypervisor that I know
does, by the way), things are simple: L0 may inject the interrupt directly
to the L2 guest - using the normal code path that injects to any guest.
We support this case in the code below.
If L1 turns on VM_EXIT_ACK_INTR_ON_EXIT, things look very different from the
description above: L1 expects to see an exit from L2 with the interrupt vector
already filled in the exit information, and does not expect to be interrupted
again with this interrupt. The current code does not (yet) support this case,
so we do not allow the VM_EXIT_ACK_INTR_ON_EXIT exit-control to be turned on
by L1.
Nadav Har'El [Wed, 25 May 2011 20:12:35 +0000 (23:12 +0300)]
KVM: nVMX: Deciding if L0 or L1 should handle an L2 exit
This patch contains the logic of whether an L2 exit should be handled by L0
and then L2 should be resumed, or whether L1 should be run to handle this
exit (using the nested_vmx_vmexit() function of the previous patch).
The basic idea is to let L1 handle the exit only if it actually asked to
trap this sort of event. For example, when L2 exits on a change to CR0,
we check L1's CR0_GUEST_HOST_MASK to see if L1 expressed interest in any
bit which changed; If it did, we exit to L1. But if it didn't it means that
it is we (L0) that wished to trap this event, so we handle it ourselves.
The next two patches add additional logic of what to do when an interrupt or
exception is injected: Does L0 need to do it, should we exit to L1 to do it,
or should we resume L2 and keep the exception to be injected later.
We keep a new flag, "nested_run_pending", which can override the decision of
which should run next, L1 or L2. nested_run_pending=1 means that we *must* run
L2 next, not L1. This is necessary in particular when L1 did a VMLAUNCH of L2
and therefore expects L2 to be run (and perhaps be injected with an event it
specified, etc.). Nested_run_pending is especially intended to avoid switching
to L1 in the injection decision-point described above.
Nadav Har'El [Wed, 25 May 2011 20:12:04 +0000 (23:12 +0300)]
KVM: nVMX: vmcs12 checks on nested entry
This patch adds a bunch of tests of the validity of the vmcs12 fields,
according to what the VMX spec and our implementation allows. If fields
we cannot (or don't want to) honor are discovered, an entry failure is
emulated.
According to the spec, there are two types of entry failures: If the problem
was in vmcs12's host state or control fields, the VMLAUNCH instruction simply
fails. But a problem is found in the guest state, the behavior is more
similar to that of an exit.
Nadav Har'El [Wed, 25 May 2011 20:11:34 +0000 (23:11 +0300)]
KVM: nVMX: Exiting from L2 to L1
This patch implements nested_vmx_vmexit(), called when the nested L2 guest
exits and we want to run its L1 parent and let it handle this exit.
Note that this will not necessarily be called on every L2 exit. L0 may decide
to handle a particular exit on its own, without L1's involvement; In that
case, L0 will handle the exit, and resume running L2, without running L1 and
without calling nested_vmx_vmexit(). The logic for deciding whether to handle
a particular exit in L1 or in L0, i.e., whether to call nested_vmx_vmexit(),
will appear in a separate patch below.
Nadav Har'El [Wed, 25 May 2011 20:11:03 +0000 (23:11 +0300)]
KVM: nVMX: No need for handle_vmx_insn function any more
Before nested VMX support, the exit handler for a guest executing a VMX
instruction (vmclear, vmlaunch, vmptrld, vmptrst, vmread, vmread, vmresume,
vmwrite, vmon, vmoff), was handle_vmx_insn(). This handler simply threw a #UD
exception. Now that all these exit reasons are properly handled (and emulate
the respective VMX instruction), nothing calls this dummy handler and it can
be removed.
Nadav Har'El [Wed, 25 May 2011 20:10:02 +0000 (23:10 +0300)]
KVM: nVMX: Prepare vmcs02 from vmcs01 and vmcs12
This patch contains code to prepare the VMCS which can be used to actually
run the L2 guest, vmcs02. prepare_vmcs02 appropriately merges the information
in vmcs12 (the vmcs that L1 built for L2) and in vmcs01 (our desires for our
own guests).
Nadav Har'El [Wed, 25 May 2011 20:09:31 +0000 (23:09 +0300)]
KVM: nVMX: Move control field setup to functions
Move some of the control field setup to common functions. These functions will
also be needed for running L2 guests - L0's desires (expressed in these
functions) will be appropriately merged with L1's desires.
Nadav Har'El [Wed, 25 May 2011 20:09:01 +0000 (23:09 +0300)]
KVM: nVMX: Move host-state field setup to a function
Move the setting of constant host-state fields (fields that do not change
throughout the life of the guest) from vmx_vcpu_setup to a new common function
vmx_set_constant_host_state(). This function will also be used to set the
host state when running L2 guests.
Nadav Har'El [Wed, 25 May 2011 20:08:30 +0000 (23:08 +0300)]
KVM: nVMX: Implement VMREAD and VMWRITE
Implement the VMREAD and VMWRITE instructions. With these instructions, L1
can read and write to the VMCS it is holding. The values are read or written
to the fields of the vmcs12 structure introduced in a previous patch.
Nadav Har'El [Wed, 25 May 2011 20:06:28 +0000 (23:06 +0300)]
KVM: nVMX: Success/failure of VMX instructions.
VMX instructions specify success or failure by setting certain RFLAGS bits.
This patch contains common functions to do this, and they will be used in
the following patches which emulate the various VMX instructions.
Nadav Har'El [Wed, 25 May 2011 20:05:57 +0000 (23:05 +0300)]
KVM: nVMX: Add VMCS fields to the vmcs12
In this patch we add to vmcs12 (the VMCS that L1 keeps for L2) all the
standard VMCS fields.
Later patches will enable L1 to read and write these fields using VMREAD/
VMWRITE, and they will be used during a VMLAUNCH/VMRESUME in preparing vmcs02,
a hardware VMCS for running L2.
Nadav Har'El [Wed, 25 May 2011 20:05:27 +0000 (23:05 +0300)]
KVM: nVMX: Introduce vmcs02: VMCS used to run L2
We saw in a previous patch that L1 controls its L2 guest with a vcms12.
L0 needs to create a real VMCS for running L2. We call that "vmcs02".
A later patch will contain the code, prepare_vmcs02(), for filling the vmcs02
fields. This patch only contains code for allocating vmcs02.
In this version, prepare_vmcs02() sets *all* of vmcs02's fields each time we
enter from L1 to L2, so keeping just one vmcs02 for the vcpu is enough: It can
be reused even when L1 runs multiple L2 guests. However, in future versions
we'll probably want to add an optimization where vmcs02 fields that rarely
change will not be set each time. For that, we may want to keep around several
vmcs02s of L2 guests that have recently run, so that potentially we could run
these L2s again more quickly because less vmwrites to vmcs02 will be needed.
This patch adds to each vcpu a vmcs02 pool, vmx->nested.vmcs02_pool,
which remembers the vmcs02s last used to run up to VMCS02_POOL_SIZE L2s.
As explained above, in the current version we choose VMCS02_POOL_SIZE=1,
I.e., one vmcs02 is allocated (and loaded onto the processor), and it is
reused to enter any L2 guest. In the future, when prepare_vmcs02() is
optimized not to set all fields every time, VMCS02_POOL_SIZE should be
increased.
Nadav Har'El [Wed, 25 May 2011 20:04:25 +0000 (23:04 +0300)]
KVM: nVMX: Implement reading and writing of VMX MSRs
When the guest can use VMX instructions (when the "nested" module option is
on), it should also be able to read and write VMX MSRs, e.g., to query about
VMX capabilities. This patch adds this support.
Nadav Har'El [Wed, 25 May 2011 20:03:55 +0000 (23:03 +0300)]
KVM: nVMX: Introduce vmcs12: a VMCS structure for L1
An implementation of VMX needs to define a VMCS structure. This structure
is kept in guest memory, but is opaque to the guest (who can only read or
write it with VMX instructions).
This patch starts to define the VMCS structure which our nested VMX
implementation will present to L1. We call it "vmcs12", as it is the VMCS
that L1 keeps for its L2 guest. We will add more content to this structure
in later patches.
This patch also adds the notion (as required by the VMX spec) of L1's "current
VMCS", and finally includes utility functions for mapping the guest-allocated
VMCSs in host memory.
Nadav Har'El [Wed, 25 May 2011 20:03:24 +0000 (23:03 +0300)]
KVM: nVMX: Allow setting the VMXE bit in CR4
This patch allows the guest to enable the VMXE bit in CR4, which is a
prerequisite to running VMXON.
Whether to allow setting the VMXE bit now depends on the architecture (svm
or vmx), so its checking has moved to kvm_x86_ops->set_cr4(). This function
now returns an int: If kvm_x86_ops->set_cr4() returns 1, __kvm_set_cr4()
will also return 1, and this will cause kvm_set_cr4() will throw a #GP.
Turning on the VMXE bit is allowed only when the nested VMX feature is
enabled, and turning it off is forbidden after a vmxon.
Nadav Har'El [Wed, 25 May 2011 20:02:54 +0000 (23:02 +0300)]
KVM: nVMX: Implement VMXON and VMXOFF
This patch allows a guest to use the VMXON and VMXOFF instructions, and
emulates them accordingly. Basically this amounts to checking some
prerequisites, and then remembering whether the guest has enabled or disabled
VMX operation.
Nadav Har'El [Wed, 25 May 2011 20:02:23 +0000 (23:02 +0300)]
KVM: nVMX: Add "nested" module option to kvm_intel
This patch adds to kvm_intel a module option "nested". This option controls
whether the guest can use VMX instructions, i.e., whether we allow nested
virtualization. A similar, but separate, option already exists for the
SVM module.
This option currently defaults to 0, meaning that nested VMX must be
explicitly enabled by giving nested=1. When nested VMX matures, the default
should probably be changed to enable nested VMX by default - just like
nested SVM is currently enabled by default.
Takuya Yoshikawa [Wed, 25 May 2011 02:09:38 +0000 (11:09 +0900)]
KVM: x86 emulator: Avoid clearing the whole decode_cache
During tracing the emulator, we noticed that init_emulate_ctxt()
sometimes took a bit longer time than we expected.
This patch is for mitigating the problem by some degree.
By looking into the function, we soon notice that it clears the whole
decode_cache whose size is about 2.5K bytes now. Furthermore, most of
the bytes are taken for the two read_cache arrays, which are used only
by a few instructions.
Considering the fact that we are not assuming the cache arrays have
been cleared when we store actual data, we do not need to clear the
arrays: 2K bytes elimination. In addition, we can avoid clearing the
fetch_cache and regs arrays.
This patch changes the initialization not to clear the arrays.
On our 64-bit host, init_emulate_ctxt() becomes 0.3 to 0.5us faster with
this patch applied.
Jan Kiszka [Mon, 23 May 2011 08:33:05 +0000 (10:33 +0200)]
KVM: Clean up error handling during VCPU creation
So far kvm_arch_vcpu_setup is responsible for freeing the vcpu struct if
it fails. Move this confusing resonsibility back into the hands of
kvm_vm_ioctl_create_vcpu. Only kvm_arch_vcpu_setup of x86 is affected,
all other archs cannot fail.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Nadav Har'El [Tue, 24 May 2011 12:26:10 +0000 (15:26 +0300)]
KVM: VMX: Keep list of loaded VMCSs, instead of vcpus
In VMX, before we bring down a CPU we must VMCLEAR all VMCSs loaded on it
because (at least in theory) the processor might not have written all of its
content back to memory. Since a patch from June 26, 2008, this is done using
a per-cpu "vcpus_on_cpu" linked list of vcpus loaded on each CPU.
The problem is that with nested VMX, we no longer have the concept of a
vcpu being loaded on a cpu: A vcpu has multiple VMCSs (one for L1, a pool for
L2s), and each of those may be have been last loaded on a different cpu.
So instead of linking the vcpus, we link the VMCSs, using a new structure
loaded_vmcs. This structure contains the VMCS, and the information pertaining
to its loading on a specific cpu (namely, the cpu number, and whether it
was already launched on this cpu once). In nested we will also use the same
structure to hold L2 VMCSs, and vmx->loaded_vmcs is a pointer to the
currently active VMCS.
Signed-off-by: Nadav Har'El <nyh@il.ibm.com> Acked-by: Acked-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Wed, 18 May 2011 09:56:07 +0000 (05:56 -0400)]
KVM: Sanitize cpuid
Instead of blacklisting known-unsupported cpuid leaves, whitelist known-
supported leaves. This is more conservative and prevents us from reporting
features we don't support. Also whitelist a few more leaves while at it.
Avi Kivity [Sun, 15 May 2011 14:13:13 +0000 (10:13 -0400)]
KVM: VMX: always_inline VMREADs
vmcs_readl() and friends are really short, but gcc thinks they are long because of
the out-of-line exception handlers. Mark them always_inline to clear the
misunderstanding.
Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Avi Kivity [Sun, 15 May 2011 14:13:12 +0000 (10:13 -0400)]
KVM: VMX: Move VMREAD cleanup to exception handler
We clean up a failed VMREAD by clearing the output register. Do
it in the exception handler instead of unconditionally. This is
worthwhile since there are more than a hundred call sites.
Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
projects / linux-beck.git / log