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KVM: nVMX: Capture VM-Fail to a local var in nested_vmx_check_vmentry_hw()

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Unlike the primary vCPU-run flow, the nested early checks code doesn't
actually want to propagate VM-Fail back to 'vmx'.  Yay copy+paste.

In additional to eliminating the need to clear vmx->fail before
returning, using a local boolean also drops a reference to 'vmx' in the
asm blob.  Dropping the reference to 'vmx' will save a register in the
long run as future patches will shift all pointer references from 'vmx'
to 'vmx->loaded_vmcs'.

Fixes: 52017608da ("KVM: nVMX: add option to perform early consistency checks via H/W")
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>
This commit is contained in:
Sean Christopherson 2019-01-25 07:40:58 -08:00 committed by Paolo Bonzini
parent 6c1e7e5b40
commit f1727b4954
1 changed files with 10 additions and 6 deletions
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16
arch/x86/kvm/vmx/nested.c
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@ -2718,6 +2718,7 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long cr3, cr4;
bool vm_fail;
if (!nested_early_check)
return 0;
@ -2763,14 +2764,18 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
/* Check if vmlaunch or vmresume is needed */
"cmpb $0, %c[launched](%% " _ASM_CX")\n\t"
/*
* VMLAUNCH and VMRESUME clear RFLAGS.{CF,ZF} on VM-Exit, set
* RFLAGS.CF on VM-Fail Invalid and set RFLAGS.ZF on VM-Fail
* Valid. vmx_vmenter() directly "returns" RFLAGS, and so the
* results of VM-Enter is captured via SETBE to vm_fail.
*/
"call vmx_vmenter\n\t"
/* Set vmx->fail accordingly */
"setbe %c[fail](%% " _ASM_CX")\n\t"
: ASM_CALL_CONSTRAINT
"setbe %[fail]\n\t"
: ASM_CALL_CONSTRAINT, [fail]"=qm"(vm_fail)
: "c"(vmx), "d"((unsigned long)HOST_RSP),
[launched]"i"(offsetof(struct vcpu_vmx, __launched)),
[fail]"i"(offsetof(struct vcpu_vmx, fail)),
[host_rsp]"i"(offsetof(struct vcpu_vmx, host_rsp)),
[wordsize]"i"(sizeof(ulong))
: "cc", "memory"
@ -2783,10 +2788,9 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
if (vmx->msr_autoload.guest.nr)
vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
if (vmx->fail) {
if (vm_fail) {
WARN_ON_ONCE(vmcs_read32(VM_INSTRUCTION_ERROR) !=
VMXERR_ENTRY_INVALID_CONTROL_FIELD);
vmx->fail = 0;
return 1;
}