* [PATCH 5/8] KVM: SVM: fix comment
2018-01-09 12:03 [PATCH v2 0/8] KVM: x86: expose CVE-2017-5715 ("Spectre variant 2") mitigations to guest Paolo Bonzini
@ 2018-01-09 12:03 ` Paolo Bonzini
2018-01-15 9:53 ` David Hildenbrand
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2018-01-09 12:03 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: rkrcmar, liran.alon, jmattson, aliguori, thomas.lendacky, dwmw,
bp, x86
If always==true, then read/write bits are cleared from
the MSR permission bitmap, thus passing-through the MSR.
Fix the comment to match reality.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 55dde3896898..31ace8d7774a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -236,7 +236,7 @@ struct amd_svm_iommu_ir {
static const struct svm_direct_access_msrs {
u32 index; /* Index of the MSR */
- bool always; /* True if intercept is always on */
+ bool always; /* True if intercept is always off */
} direct_access_msrs[] = {
{ .index = MSR_STAR, .always = true },
{ .index = MSR_IA32_SYSENTER_CS, .always = true },
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 5/8] KVM: SVM: fix comment
@ 2018-01-09 13:17 Liran Alon
0 siblings, 0 replies; 3+ messages in thread
From: Liran Alon @ 2018-01-09 13:17 UTC (permalink / raw)
To: pbonzini
Cc: jmattson, x86, dwmw, bp, thomas.lendacky, aliguori, rkrcmar,
linux-kernel, kvm
----- pbonzini@redhat.com wrote:
> If always==true, then read/write bits are cleared from
> the MSR permission bitmap, thus passing-through the MSR.
> Fix the comment to match reality.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/svm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 55dde3896898..31ace8d7774a 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -236,7 +236,7 @@ struct amd_svm_iommu_ir {
>
> static const struct svm_direct_access_msrs {
> u32 index; /* Index of the MSR */
> - bool always; /* True if intercept is always on */
> + bool always; /* True if intercept is always off */
> } direct_access_msrs[] = {
> { .index = MSR_STAR, .always = true },
> { .index = MSR_IA32_SYSENTER_CS, .always = true },
> --
> 1.8.3.1
Reviewed-by: Liran Alon <liran.alon@oracle.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 5/8] KVM: SVM: fix comment
2018-01-09 12:03 ` [PATCH 5/8] KVM: SVM: fix comment Paolo Bonzini
@ 2018-01-15 9:53 ` David Hildenbrand
0 siblings, 0 replies; 3+ messages in thread
From: David Hildenbrand @ 2018-01-15 9:53 UTC (permalink / raw)
To: Paolo Bonzini, linux-kernel, kvm
Cc: rkrcmar, liran.alon, jmattson, aliguori, thomas.lendacky, dwmw,
bp, x86
On 09.01.2018 13:03, Paolo Bonzini wrote:
> If always==true, then read/write bits are cleared from
> the MSR permission bitmap, thus passing-through the MSR.
> Fix the comment to match reality.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/svm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 55dde3896898..31ace8d7774a 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -236,7 +236,7 @@ struct amd_svm_iommu_ir {
>
> static const struct svm_direct_access_msrs {
> u32 index; /* Index of the MSR */
> - bool always; /* True if intercept is always on */
> + bool always; /* True if intercept is always off */
> } direct_access_msrs[] = {
> { .index = MSR_STAR, .always = true },
> { .index = MSR_IA32_SYSENTER_CS, .always = true },
>
The function set_msr_interception() is really named confusingly.
If we pass in a "1", we clear the bit, resulting in no interception.
So 1==no intercept, 0==intercept. This function would be better named
"disable_msr_interception" or sth. like that.
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 3+ messages in thread
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