Commit Graph

782903 Commits

Author SHA1 Message Date
Uros Bizjak
44c2d667ce KVM/x86: Use 32bit xor to clear register
x86_64 zero-extends 32bit xor to a full 64bit register. Use %k asm
operand modifier to force 32bit register and save 268 bytes in kvm.o

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:09 +02:00
Uros Bizjak
4b1e54786e KVM/x86: Use assembly instruction mnemonics instead of .byte streams
Recently the minimum required version of binutils was changed to 2.20,
which supports all VMX instruction mnemonics. The patch removes
all .byte #defines and uses real instruction mnemonics instead.

The compiler is now able to pass memory operand to the instruction,
so there is no need for memory clobber anymore. Also, the compiler
adds CC register clobber automatically to all extended asm clauses,
so the patch also removes explicit CC clobber.

The immediate benefit of the patch is removal of many unnecesary
register moves, resulting in 1434 saved bytes in vmx.o:

   text    data     bss     dec     hex filename
 151257   18246    8500  178003   2b753 vmx.o
 152691   18246    8500  179437   2bced vmx-old.o

Some examples of improvement include removal of unneeded moves
of %rsp to %rax in front of invept and invvpid instructions:

    a57e:	b9 01 00 00 00       	mov    $0x1,%ecx
    a583:	48 89 04 24          	mov    %rax,(%rsp)
    a587:	48 89 e0             	mov    %rsp,%rax
    a58a:	48 c7 44 24 08 00 00 	movq   $0x0,0x8(%rsp)
    a591:	00 00
    a593:	66 0f 38 80 08       	invept (%rax),%rcx

to:

    a45c:	48 89 04 24          	mov    %rax,(%rsp)
    a460:	b8 01 00 00 00       	mov    $0x1,%eax
    a465:	48 c7 44 24 08 00 00 	movq   $0x0,0x8(%rsp)
    a46c:	00 00
    a46e:	66 0f 38 80 04 24    	invept (%rsp),%rax

and the ability to use more optimal registers and memory operands
in the instruction:

    8faa:	48 8b 44 24 28       	mov    0x28(%rsp),%rax
    8faf:	4c 89 c2             	mov    %r8,%rdx
    8fb2:	0f 79 d0             	vmwrite %rax,%rdx

to:

    8e7c:	44 0f 79 44 24 28    	vmwrite 0x28(%rsp),%r8

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:08 +02:00
Uros Bizjak
5ebb272b2e KVM/x86: Fix invvpid and invept register operand size in 64-bit mode
Register operand size of invvpid and invept instruction in 64-bit mode
has always 64 bits. Adjust inline function argument type to reflect
correct size.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:07 +02:00
Vitaly Kuznetsov
bf627a9288 x86/kvm/mmu: check if MMU reconfiguration is needed in init_kvm_nested_mmu()
We don't use root page role for nested_mmu, however, optimizing out
re-initialization in case nothing changed is still valuable as this
is done for every nested vmentry.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:07 +02:00
Vitaly Kuznetsov
7dcd575520 x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed
MMU reconfiguration in init_kvm_tdp_mmu()/kvm_init_shadow_mmu() can be
avoided if the source data used to configure it didn't change; enhance
MMU extended role with the required fields and consolidate common code in
kvm_calc_mmu_role_common().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:06 +02:00
Vitaly Kuznetsov
a336282d77 x86/kvm/nVMX: introduce source data cache for kvm_init_shadow_ept_mmu()
MMU re-initialization is expensive, in particular,
update_permission_bitmask() and update_pkru_bitmask() are.

Cache the data used to setup shadow EPT MMU and avoid full re-init when
it is unchanged.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:06 +02:00
Vitaly Kuznetsov
36d9594dfb x86/kvm/mmu: make space for source data caching in struct kvm_mmu
In preparation to MMU reconfiguration avoidance we need a space to
cache source data. As this partially intersects with kvm_mmu_page_role,
create 64bit sized union kvm_mmu_role holding both base and extended data.
No functional change.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:05 +02:00
Paolo Bonzini
e173299101 x86/kvm/mmu: get rid of redundant kvm_mmu_setup()
Just inline the contents into the sole caller, kvm_init_mmu is now
public.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
2018-10-17 00:30:04 +02:00
Vitaly Kuznetsov
14c07ad89f x86/kvm/mmu: introduce guest_mmu
When EPT is used for nested guest we need to re-init MMU as shadow
EPT MMU (nested_ept_init_mmu_context() does that). When we return back
from L2 to L1 kvm_mmu_reset_context() in nested_vmx_load_cr3() resets
MMU back to normal TDP mode. Add a special 'guest_mmu' so we can use
separate root caches; the improved hit rate is not very important for
single vCPU performance, but it avoids contention on the mmu_lock for
many vCPUs.

On the nested CPUID benchmark, with 16 vCPUs, an L2->L1->L2 vmexit
goes from 42k to 26k cycles.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:04 +02:00
Vitaly Kuznetsov
6a82cd1c7b x86/kvm/mmu.c: add kvm_mmu parameter to kvm_mmu_free_roots()
Add an option to specify which MMU root we want to free. This will
be used when nested and non-nested MMUs for L1 are split.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
2018-10-17 00:30:03 +02:00
Vitaly Kuznetsov
3dc773e745 x86/kvm/mmu.c: set get_pdptr hook in kvm_init_shadow_ept_mmu()
kvm_init_shadow_ept_mmu() doesn't set get_pdptr() hook and is this
not a problem just because MMU context is already initialized and this
hook points to kvm_pdptr_read(). As we're intended to use a dedicated
MMU for shadow EPT MMU set this hook explicitly.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
2018-10-17 00:30:03 +02:00
Vitaly Kuznetsov
44dd3ffa7b x86/kvm/mmu: make vcpu->mmu a pointer to the current MMU
As a preparation to full MMU split between L1 and L2 make vcpu->arch.mmu
a pointer to the currently used mmu. For now, this is always
vcpu->arch.root_mmu. No functional change.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
2018-10-17 00:30:02 +02:00
Paolo Bonzini
0e0a53c551 kvm: x86: optimize dr6 restore
The quote from the comment almost says it all: we are currently zeroing
the guest dr6 in kvm_arch_vcpu_put, because do_debug expects it.  However,
the host %dr6 is either:

- zero because the guest hasn't run after kvm_arch_vcpu_load

- written from vcpu->arch.dr6 by vcpu_enter_guest

- written by the guest and copied to vcpu->arch.dr6 by ->sync_dirty_debug_regs().

Therefore, we can skip the write if vcpu->arch.dr6 is already zero.  We
may do extra useless writes if vcpu->arch.dr6 is nonzero but the guest
hasn't run; however that is less important for performance.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:02 +02:00
Vitaly Kuznetsov
f21dd49450 KVM: x86: hyperv: optimize sparse VP set processing
Rewrite kvm_hv_flush_tlb()/send_ipi_vcpus_mask() making them cleaner and
somewhat more optimal.

hv_vcpu_in_sparse_set() is converted to sparse_set_to_vcpu_mask()
which copies sparse banks u64-at-a-time and then, depending on the
num_mismatched_vp_indexes value, returns immediately or does
vp index to vcpu index conversion by walking all vCPUs.

To support the change and make kvm_hv_send_ipi() look similar to
kvm_hv_flush_tlb() send_ipi_vcpus_mask() is introduced.

Suggested-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:01 +02:00
Vitaly Kuznetsov
e6b6c483eb KVM: x86: hyperv: fix 'tlb_lush' typo
Regardless of whether your TLB is lush or not it still needs flushing.

Reported-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:00 +02:00
Sean Christopherson
2768c0cc4a KVM: nVMX: WARN if nested run hits VMFail with early consistency checks enabled
When early consistency checks are enabled, all VMFail conditions
should be caught by nested_vmx_check_vmentry_hw().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:30:00 +02:00
Sean Christopherson
52017608da KVM: nVMX: add option to perform early consistency checks via H/W
KVM defers many VMX consistency checks to the CPU, ostensibly for
performance reasons[1], including checks that result in VMFail (as
opposed to VMExit).  This behavior may be undesirable for some users
since this means KVM detects certain classes of VMFail only after it
has processed guest state, e.g. emulated MSR load-on-entry.  Because
there is a strict ordering between checks that cause VMFail and those
that cause VMExit, i.e. all VMFail checks are performed before any
checks that cause VMExit, we can detect (almost) all VMFail conditions
via a dry run of sorts.  The almost qualifier exists because some
state in vmcs02 comes from L0, e.g. VPID, which means that hardware
will never detect an invalid VPID in vmcs12 because it never sees
said value.  Software must (continue to) explicitly check such fields.

After preparing vmcs02 with all state needed to pass the VMFail
consistency checks, optionally do a "test" VMEnter with an invalid
GUEST_RFLAGS.  If the VMEnter results in a VMExit (due to bad guest
state), then we can safely say that the nested VMEnter should not
VMFail, i.e. any VMFail encountered in nested_vmx_vmexit() must
be due to an L0 bug.  GUEST_RFLAGS is used to induce VMExit as it
is unconditionally loaded on all implementations of VMX, has an
invalid value that is writable on a 32-bit system and its consistency
check is performed relatively early in all implementations (the exact
order of consistency checks is micro-architectural).

Unfortunately, since the "passing" case causes a VMExit, KVM must
be extra diligent to ensure that host state is restored, e.g. DR7
and RFLAGS are reset on VMExit.  Failure to restore RFLAGS.IF is
particularly fatal.

And of course the extra VMEnter and VMExit impacts performance.
The raw overhead of the early consistency checks is ~6% on modern
hardware (though this could easily vary based on configuration),
while the added latency observed from the L1 VMM is ~10%.  The
early consistency checks do not occur in a vacuum, e.g. spending
more time in L0 can lead to more interrupts being serviced while
emulating VMEnter, thereby increasing the latency observed by L1.

Add a module param, early_consistency_checks, to provide control
over whether or not VMX performs the early consistency checks.
In addition to standard on/off behavior, the param accepts a value
of -1, which is essentialy an "auto" setting whereby KVM does
the early checks only when it thinks it's running on bare metal.
When running nested, doing early checks is of dubious value since
the resulting behavior is heavily dependent on L0.  In the future,
the "auto" setting could also be used to default to skipping the
early hardware checks for certain configurations/platforms if KVM
reaches a state where it has 100% coverage of VMFail conditions.

[1] To my knowledge no one has implemented and tested full software
    emulation of the VMFail consistency checks.  Until that happens,
    one can only speculate about the actual performance overhead of
    doing all VMFail consistency checks in software.  Obviously any
    code is slower than no code, but in the grand scheme of nested
    virtualization it's entirely possible the overhead is negligible.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:59 +02:00
Sean Christopherson
5a5e8a15d7 KVM: vmx: write HOST_IA32_EFER in vmx_set_constant_host_state()
EFER is constant in the host and writing it once during setup means
we can skip writing the host value in add_atomic_switch_msr_special().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:59 +02:00
Sean Christopherson
09abb5e3e5 KVM: nVMX: call kvm_skip_emulated_instruction in nested_vmx_{fail,succeed}
... as every invocation of nested_vmx_{fail,succeed} is immediately
followed by a call to kvm_skip_emulated_instruction().  This saves
a bit of code and eliminates some silly paths, e.g. nested_vmx_run()
ended up with a goto label purely used to call and return
kvm_skip_emulated_instruction().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:58 +02:00
Sean Christopherson
c37a6116d8 KVM: nVMX: do not call nested_vmx_succeed() for consistency check VMExit
EFLAGS is set to a fixed value on VMExit, calling nested_vmx_succeed()
is unnecessary and wrong.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:57 +02:00
Sean Christopherson
cb61de2f48 KVM: nVMX: do not skip VMEnter instruction that succeeds
A successful VMEnter is essentially a fancy indirect branch that
pulls the target RIP from the VMCS.  Skipping the instruction is
unnecessary (RIP will get overwritten by the VMExit handler) and
is problematic because it can incorrectly suppress a #DB due to
EFLAGS.TF when a VMFail is detected by hardware (happens after we
skip the instruction).

Now that vmx_nested_run() is not prematurely skipping the instr,
use the full kvm_skip_emulated_instruction() in the VMFail path
of nested_vmx_vmexit().  We also need to explicitly update the
GUEST_INTERRUPTIBILITY_INFO when loading vmcs12 host state.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:57 +02:00
Sean Christopherson
16fb9a46c5 KVM: nVMX: do early preparation of vmcs02 before check_vmentry_postreqs()
In anticipation of using vmcs02 to do early consistency checks, move
the early preparation of vmcs02 prior to checking the postreqs.  The
downside of this approach is that we'll unnecessary load vmcs02 in
the case that check_vmentry_postreqs() fails, but that is essentially
our slow path anyways (not actually slow, but it's the path we don't
really care about optimizing).

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:56 +02:00
Sean Christopherson
9d6105b2b5 KVM: nVMX: initialize vmcs02 constant exactly once (per VMCS)
Add a dedicated flag to track if vmcs02 has been initialized, i.e.
the constant state for vmcs02 has been written to the backing VMCS.
The launched flag (in struct loaded_vmcs) gets cleared on logical
CPU migration to mirror hardware behavior[1], i.e. using the launched
flag to determine whether or not vmcs02 constant state needs to be
initialized results in unnecessarily re-initializing the VMCS when
migrating between logical CPUS.

[1] The active VMCS needs to be VMCLEARed before it can be migrated
    to a different logical CPU.  Hardware's VMCS cache is per-CPU
    and is not coherent between CPUs.  VMCLEAR flushes the cache so
    that any dirty data is written back to memory.  A side effect
    of VMCLEAR is that it also clears the VMCS's internal launch
    flag, which KVM must mirror because VMRESUME must be used to
    run a previously launched VMCS.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:56 +02:00
Sean Christopherson
09abe32002 KVM: nVMX: split pieces of prepare_vmcs02() to prepare_vmcs02_early()
Add prepare_vmcs02_early() and move pieces of prepare_vmcs02() to the
new function.  prepare_vmcs02_early() writes the bits of vmcs02 that
a) must be in place to pass the VMFail consistency checks (assuming
vmcs12 is valid) and b) are needed recover from a VMExit, e.g. host
state that is loaded on VMExit.  Splitting the functionality will
enable KVM to leverage hardware to do VMFail consistency checks via
a dry run of VMEnter and recover from a potential VMExit without
having to fully initialize vmcs02.

Add prepare_vmcs02_constant_state() to handle writing vmcs02 state that
comes from vmcs01 and never changes, i.e. we don't need to rewrite any
of the vmcs02 that is effectively constant once defined.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:55 +02:00
Sean Christopherson
860ff2aa84 KVM: VMX: remove ASSERT() on vmx->pml_pg validity
vmx->pml_pg is allocated by vmx_create_vcpu() and is only nullified
when the vCPU is destroyed by vmx_free_vcpu().  Remove the ASSERTs
on vmx->pml_pg, there is no need to carry debug code that provides
no value to the current code base.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:55 +02:00
Sean Christopherson
39f9c3885c KVM: vVMX: rename label for post-enter_guest_mode consistency check
Rename 'fail' to 'vmentry_fail_vmexit_guest_mode' to make it more
obvious that it's simply a different entry point to the VMExit path,
whose purpose is unwind the updates done prior to calling
prepare_vmcs02().

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:54 +02:00
Sean Christopherson
a633e41e73 KVM: nVMX: assimilate nested_vmx_entry_failure() into nested_vmx_enter_non_root_mode()
Handling all VMExits due to failed consistency checks on VMEnter in
nested_vmx_enter_non_root_mode() consolidates all relevant code into
a single location, and removing nested_vmx_entry_failure() eliminates
a confusing function name and label.  For a VMEntry, "fail" and its
derivatives has a very specific meaning due to the different behavior
of a VMEnter VMFail versus VMExit, i.e. it wasn't obvious that
nested_vmx_entry_failure() handled VMExit scenarios.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:53 +02:00
Sean Christopherson
7671ce21b1 KVM: nVMX: move check_vmentry_postreqs() call to nested_vmx_enter_non_root_mode()
In preparation of supporting checkpoint/restore for nested state,
commit ca0bde28f2 ("kvm: nVMX: Split VMCS checks from nested_vmx_run()")
modified check_vmentry_postreqs() to only perform the guest EFER
consistency checks when nested_run_pending is true.  But, in the
normal nested VMEntry flow, nested_run_pending is only set after
check_vmentry_postreqs(), i.e. the consistency check is being skipped.

Alternatively, nested_run_pending could be set prior to calling
check_vmentry_postreqs() in nested_vmx_run(), but placing the
consistency checks in nested_vmx_enter_non_root_mode() allows us
to split prepare_vmcs02() and interleave the preparation with
the consistency checks without having to change the call sites
of nested_vmx_enter_non_root_mode().  In other words, the rest
of the consistency check code in nested_vmx_run() will be joining
the postreqs checks in future patches.

Fixes: ca0bde28f2 ("kvm: nVMX: Split VMCS checks from nested_vmx_run()")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jim Mattson <jmattson@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:53 +02:00
Sean Christopherson
d63907dc7d KVM: nVMX: rename enter_vmx_non_root_mode to nested_vmx_enter_non_root_mode
...to be more consistent with the nested VMX nomenclature.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:52 +02:00
Sean Christopherson
3df5c37e55 KVM: nVMX: try to set EFER bits correctly when initializing controls
VM_ENTRY_IA32E_MODE and VM_{ENTRY,EXIT}_LOAD_IA32_EFER will be
explicitly set/cleared as needed by vmx_set_efer(), but attempt
to get the bits set correctly when intializing the control fields.
Setting the value correctly can avoid multiple VMWrites.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:52 +02:00
Sean Christopherson
02343cf207 KVM: vmx: do not unconditionally clear EFER switching
Do not unconditionally call clear_atomic_switch_msr() when updating
EFER.  This adds up to four unnecessary VMWrites in the case where
guest_efer != host_efer, e.g. if the load_on_{entry,exit} bits were
already set.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:51 +02:00
Sean Christopherson
b7031fd40f KVM: nVMX: reset cache/shadows when switching loaded VMCS
Reset the vm_{entry,exit}_controls_shadow variables as well as the
segment cache after loading a new VMCS in vmx_switch_vmcs().  The
shadows/cache track VMCS data, i.e. they're stale every time we
switch to a new VMCS regardless of reason.

This fixes a bug where stale control shadows would be consumed after
a nested VMExit due to a failed consistency check.

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:50 +02:00
Sean Christopherson
1abf23fb42 KVM: nVMX: use vm_exit_controls_init() to write exit controls for vmcs02
Write VM_EXIT_CONTROLS using vm_exit_controls_init() when configuring
vmcs02, otherwise vm_exit_controls_shadow will be stale.  EFER in
particular can be corrupted if VM_EXIT_LOAD_IA32_EFER is not updated
due to an incorrect shadow optimization, which can crash L0 due to
EFER not being loaded on exit.  This does not occur with the current
code base simply because update_transition_efer() unconditionally
clears VM_EXIT_LOAD_IA32_EFER before conditionally setting it, and
because a nested guest always starts with VM_EXIT_LOAD_IA32_EFER
clear, i.e. we'll only ever unnecessarily clear the bit.  That is,
until someone optimizes update_transition_efer()...

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:50 +02:00
Sean Christopherson
5b8ba41daf KVM: nVMX: move vmcs12 EPTP consistency check to check_vmentry_prereqs()
An invalid EPTP causes a VMFail(VMXERR_ENTRY_INVALID_CONTROL_FIELD),
not a VMExit.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:49 +02:00
Sean Christopherson
64a919f7b5 KVM: nVMX: move host EFER consistency checks to VMFail path
Invalid host state related to loading EFER on VMExit causes a
VMFail(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD), not a VMExit.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:49 +02:00
Wei Yang
31fc4f95dd KVM: leverage change to adjust slots->used_slots in update_memslots()
update_memslots() is only called by __kvm_set_memory_region(), in which
"change" is calculated and indicates how to adjust slots->used_slots

  * increase by one if it is KVM_MR_CREATE
  * decrease by one if it is KVM_MR_DELETE
  * not change for others

This patch adjusts slots->used_slots in update_memslots() based on "change"
value instead of re-calculate those states again.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:48 +02:00
Jim Mattson
3c6e099fa1 KVM: nVMX: Always reflect #NM VM-exits to L1
When bit 3 (corresponding to CR0.TS) of the VMCS12 cr0_guest_host_mask
field is clear, the VMCS12 guest_cr0 field does not necessarily hold
the current value of the L2 CR0.TS bit, so the code that checked for
L2's CR0.TS bit being set was incorrect. Moreover, I'm not sure that
the CR0.TS check was adequate. (What if L2's CR0.EM was set, for
instance?)

Fortunately, lazy FPU has gone away, so L0 has lost all interest in
intercepting #NM exceptions. See commit bd7e5b0899 ("KVM: x86:
remove code for lazy FPU handling"). Therefore, there is no longer any
question of which hypervisor gets first dibs. The #NM VM-exit should
always be reflected to L1. (Note that the corresponding bit must be
set in the VMCS12 exception_bitmap field for there to be an #NM
VM-exit at all.)

Fixes: ccf9844e5d ("kvm, vmx: Really fix lazy FPU on nested guest")
Reported-by: Abhiroop Dabral <adabral@paloaltonetworks.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Tested-by: Abhiroop Dabral <adabral@paloaltonetworks.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:47 +02:00
Vitaly Kuznetsov
214ff83d44 KVM: x86: hyperv: implement PV IPI send hypercalls
Using hypercall for sending IPIs is faster because this allows to specify
any number of vCPUs (even > 64 with sparse CPU set), the whole procedure
will take only one VMEXIT.

Current Hyper-V TLFS (v5.0b) claims that HvCallSendSyntheticClusterIpi
hypercall can't be 'fast' (passing parameters through registers) but
apparently this is not true, Windows always uses it as 'fast' so we need
to support that.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:47 +02:00
Vitaly Kuznetsov
2cefc5feb8 KVM: x86: hyperv: optimize kvm_hv_flush_tlb() for vp_index == vcpu_idx case
VP inedx almost always matches VCPU and when it does it's faster to walk
the sparse set instead of all vcpus.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:46 +02:00
Vitaly Kuznetsov
0b0a31badb KVM: x86: hyperv: valid_bank_mask should be 'u64'
This probably doesn't matter much (KVM_MAX_VCPUS is much lower nowadays)
but valid_bank_mask is really u64 and not unsigned long.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:46 +02:00
Vitaly Kuznetsov
87ee613d07 KVM: x86: hyperv: keep track of mismatched VP indexes
In most common cases VP index of a vcpu matches its vcpu index. Userspace
is, however, free to set any mapping it wishes and we need to account for
that when we need to find a vCPU with a particular VP index. To keep search
algorithms optimal in both cases introduce 'num_mismatched_vp_indexes'
counter showing how many vCPUs with mismatching VP index we have. In case
the counter is zero we can assume vp_index == vcpu_idx.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:45 +02:00
Vitaly Kuznetsov
1779a39f78 KVM: x86: hyperv: consistently use 'hv_vcpu' for 'struct kvm_vcpu_hv' variables
Rename 'hv' to 'hv_vcpu' in kvm_hv_set_msr/kvm_hv_get_msr(); 'hv' is
'reserved' for 'struct kvm_hv' variables across the file.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:45 +02:00
Vitaly Kuznetsov
a812297c4f KVM: x86: hyperv: optimize 'all cpus' case in kvm_hv_flush_tlb()
We can use 'NULL' to represent 'all cpus' case in
kvm_make_vcpus_request_mask() and avoid building vCPU mask with
all vCPUs.

Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:44 +02:00
Vitaly Kuznetsov
9170200ec0 KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS
Hyper-V TLFS (5.0b) states:

> Virtual processors are identified by using an index (VP index). The
> maximum number of virtual processors per partition supported by the
> current implementation of the hypervisor can be obtained through CPUID
> leaf 0x40000005. A virtual processor index must be less than the
> maximum number of virtual processors per partition.

Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx()
can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:43 +02:00
Paolo Bonzini
0624fca951 kvm/x86: return meaningful value from KVM_SIGNAL_MSI
If kvm_apic_map_get_dest_lapic() finds a disabled LAPIC,
it will return with bitmap==0 and (*r == -1) will be returned to
userspace.

QEMU may then record "KVM: injection failed, MSI lost
(Operation not permitted)" in its log, which is quite puzzling.

Reported-by: Peng Hao <penghao122@sina.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:43 +02:00
Wei Yang
4fef0f4913 KVM: x86: move definition PT_MAX_HUGEPAGE_LEVEL and KVM_NR_PAGE_SIZES together
Currently, there are two definitions related to huge page, but a little bit
far from each other and seems loosely connected:

 * KVM_NR_PAGE_SIZES defines the number of different size a page could map
 * PT_MAX_HUGEPAGE_LEVEL means the maximum level of huge page

The number of different size a page could map equals the maximum level
of huge page, which is implied by current definition.

While current implementation may not be kind to readers and further
developers:

 * KVM_NR_PAGE_SIZES looks like a stand alone definition at first sight
 * in case we need to support more level, two places need to change

This patch tries to make these two definition more close, so that reader
and developer would feel more comfortable to manipulate.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:42 +02:00
Tianyu Lan
aaa45da24e KVM/VMX: Remve unused function is_external_interrupt().
is_external_interrupt() is not used now and so remove it.

Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:42 +02:00
Wei Yang
daefb7949e KVM: x86: return 0 in case kvm_mmu_memory_cache has min number of objects
The code tries to pre-allocate *min* number of objects, so it is ok to
return 0 when the kvm_mmu_memory_cache meets the requirement.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:41 +02:00
Krish Sadhukhan
55c1dcd80b nVMX x86: Make nested_vmx_check_pml_controls() concise
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:41 +02:00
Wei Yang
3ff519f29d KVM: x86: adjust kvm_mmu_page member to save 8 bytes
On a 64bits machine, struct is naturally aligned with 8 bytes. Since
kvm_mmu_page member *unsync* and *role* are less then 4 bytes, we can
rearrange the sequence to compace the struct.

As the comment shows, *role* and *gfn* are used to key the shadow page. In
order to keep the comment valid, this patch moves the *unsync* up and
exchange the position of *role* and *gfn*.

From /proc/slabinfo, it shows the size of kvm_mmu_page is 8 bytes less and
with one more object per slap after applying this patch.

    # name            <active_objs> <num_objs> <objsize> <objperslab>
    kvm_mmu_page_header      0           0       168         24

    kvm_mmu_page_header      0           0       160         25

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17 00:29:40 +02:00