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KVM: nVMX/nSVM: Fix bug which sets vcpu->arch.tsc_offset to L1 tsc_offset

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Since commit e79f245dde ("X86/KVM: Properly update 'tsc_offset' to
represent the running guest"), vcpu->arch.tsc_offset meaning was
changed to always reflect the tsc_offset value set on active VMCS.
Regardless if vCPU is currently running L1 or L2.

However, above mentioned commit failed to also change
kvm_vcpu_write_tsc_offset() to set vcpu->arch.tsc_offset correctly.
This is because vmx_write_tsc_offset() could set the tsc_offset value
in active VMCS to given offset parameter *plus vmcs12->tsc_offset*.
However, kvm_vcpu_write_tsc_offset() just sets vcpu->arch.tsc_offset
to given offset parameter. Without taking into account the possible
addition of vmcs12->tsc_offset. (Same is true for SVM case).

Fix this issue by changing kvm_x86_ops->write_tsc_offset() to return
actually set tsc_offset in active VMCS and modify
kvm_vcpu_write_tsc_offset() to set returned value in
vcpu->arch.tsc_offset.
In addition, rename write_tsc_offset() callback to write_l1_tsc_offset()
to make it clear that it is meant to set L1 TSC offset.

Fixes: e79f245dde ("X86/KVM: Properly update 'tsc_offset' to represent the running guest")
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Leonid Shatz <leonid.shatz@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Leonid Shatz
2018-11-06 12:14:25 +02:00
committed by Paolo Bonzini
parent 1e4329ee2c
commit 326e742533
4 changed files with 17 additions and 18 deletions
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5
arch/x86/kvm/svm.c
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@@ -1446,7 +1446,7 @@ static u64 svm_read_l1_tsc_offset(struct kvm_vcpu *vcpu)
return vcpu->arch.tsc_offset;
}
static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
static u64 svm_write_l1_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
struct vcpu_svm *svm = to_svm(vcpu);
u64 g_tsc_offset = 0;
@@ -1464,6 +1464,7 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
svm->vmcb->control.tsc_offset = offset + g_tsc_offset;
mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
return svm->vmcb->control.tsc_offset;
}
static void avic_init_vmcb(struct vcpu_svm *svm)
@@ -7152,7 +7153,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.has_wbinvd_exit = svm_has_wbinvd_exit,
.read_l1_tsc_offset = svm_read_l1_tsc_offset,
.write_tsc_offset = svm_write_tsc_offset,
.write_l1_tsc_offset = svm_write_l1_tsc_offset,
.set_tdp_cr3 = set_tdp_cr3,