* [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
@ 2014-01-21 18:59 Liu, Jinsong
2014-01-22 10:21 ` Paolo Bonzini
2014-01-22 11:05 ` Paolo Bonzini
0 siblings, 2 replies; 4+ messages in thread
From: Liu, Jinsong @ 2014-01-21 18:59 UTC (permalink / raw)
To: Paolo Bonzini
Cc: gleb@redhat.com, kvm@vger.kernel.org, qemu-devel@nongnu.org,
linux-kernel@vger.kernel.org, hpa@zytor.com, Ren, Qiaowei
>From 3155a190ce6ebb213e6c724240f4e6620ba67a9d Mon Sep 17 00:00:00 2001
From: Liu Jinsong <jinsong.liu@intel.com>
Date: Fri, 13 Dec 2013 02:32:03 +0800
Subject: [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
EBX of cpuid(0xD, 0) is dynamic per XCR0 features enable/disable.
Bit 63 of XCR0 is reserved for future expansion.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
---
arch/x86/include/asm/xsave.h | 2 ++
arch/x86/kvm/cpuid.c | 6 +++---
arch/x86/kvm/x86.c | 7 +++++--
3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 5547389..f6c4e85 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -13,6 +13,8 @@
#define XSTATE_BNDCSR 0x10
#define XSTATE_FPSSE (XSTATE_FP | XSTATE_SSE)
+/* Bit 63 of XCR0 is reserved for future expansion */
+#define XSTATE_EXTEND_MASK (~(XSTATE_FPSSE | (1 << 63)))
#define FXSAVE_SIZE 512
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index c697625..2d661e6 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -28,7 +28,7 @@ static u32 xstate_required_size(u64 xstate_bv)
int feature_bit = 0;
u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
- xstate_bv &= ~XSTATE_FPSSE;
+ xstate_bv &= XSTATE_EXTEND_MASK;
while (xstate_bv) {
if (xstate_bv & 0x1) {
u32 eax, ebx, ecx, edx;
@@ -74,8 +74,8 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
vcpu->arch.guest_supported_xcr0 =
(best->eax | ((u64)best->edx << 32)) &
host_xcr0 & KVM_SUPPORTED_XCR0;
- vcpu->arch.guest_xstate_size =
- xstate_required_size(vcpu->arch.guest_supported_xcr0);
+ vcpu->arch.guest_xstate_size = best->ebx =
+ xstate_required_size(vcpu->arch.xcr0);
}
kvm_pmu_cpuid_update(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 21ef1ba..1657ca2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -576,13 +576,13 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
- u64 xcr0;
+ u64 xcr0 = xcr;
+ u64 old_xcr0 = vcpu->arch.xcr0;
u64 valid_bits;
/* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */
if (index != XCR_XFEATURE_ENABLED_MASK)
return 1;
- xcr0 = xcr;
if (!(xcr0 & XSTATE_FP))
return 1;
if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
@@ -599,6 +599,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
kvm_put_guest_xcr0(vcpu);
vcpu->arch.xcr0 = xcr0;
+
+ if ((xcr0 ^ old_xcr0) & XSTATE_EXTEND_MASK)
+ kvm_update_cpuid(vcpu);
return 0;
}
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
2014-01-21 18:59 [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug Liu, Jinsong
@ 2014-01-22 10:21 ` Paolo Bonzini
2014-01-22 10:31 ` H. Peter Anvin
2014-01-22 11:05 ` Paolo Bonzini
1 sibling, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2014-01-22 10:21 UTC (permalink / raw)
To: hpa@zytor.com
Cc: Liu, Jinsong, gleb@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, Ren, Qiaowei
Il 21/01/2014 19:59, Liu, Jinsong ha scritto:
> From 3155a190ce6ebb213e6c724240f4e6620ba67a9d Mon Sep 17 00:00:00 2001
> From: Liu Jinsong <jinsong.liu@intel.com>
> Date: Fri, 13 Dec 2013 02:32:03 +0800
> Subject: [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
>
> EBX of cpuid(0xD, 0) is dynamic per XCR0 features enable/disable.
> Bit 63 of XCR0 is reserved for future expansion.
>
> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Peter, can I have your acked-by on this?
> ---
> arch/x86/include/asm/xsave.h | 2 ++
> arch/x86/kvm/cpuid.c | 6 +++---
> arch/x86/kvm/x86.c | 7 +++++--
> 3 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
> index 5547389..f6c4e85 100644
> --- a/arch/x86/include/asm/xsave.h
> +++ b/arch/x86/include/asm/xsave.h
> @@ -13,6 +13,8 @@
> #define XSTATE_BNDCSR 0x10
>
> #define XSTATE_FPSSE (XSTATE_FP | XSTATE_SSE)
> +/* Bit 63 of XCR0 is reserved for future expansion */
> +#define XSTATE_EXTEND_MASK (~(XSTATE_FPSSE | (1 << 63)))
>
> #define FXSAVE_SIZE 512
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index c697625..2d661e6 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -28,7 +28,7 @@ static u32 xstate_required_size(u64 xstate_bv)
> int feature_bit = 0;
> u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
>
> - xstate_bv &= ~XSTATE_FPSSE;
> + xstate_bv &= XSTATE_EXTEND_MASK;
> while (xstate_bv) {
> if (xstate_bv & 0x1) {
> u32 eax, ebx, ecx, edx;
> @@ -74,8 +74,8 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
> vcpu->arch.guest_supported_xcr0 =
> (best->eax | ((u64)best->edx << 32)) &
> host_xcr0 & KVM_SUPPORTED_XCR0;
> - vcpu->arch.guest_xstate_size =
> - xstate_required_size(vcpu->arch.guest_supported_xcr0);
> + vcpu->arch.guest_xstate_size = best->ebx =
> + xstate_required_size(vcpu->arch.xcr0);
> }
>
> kvm_pmu_cpuid_update(vcpu);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 21ef1ba..1657ca2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -576,13 +576,13 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
>
> int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
> {
> - u64 xcr0;
> + u64 xcr0 = xcr;
> + u64 old_xcr0 = vcpu->arch.xcr0;
> u64 valid_bits;
>
> /* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */
> if (index != XCR_XFEATURE_ENABLED_MASK)
> return 1;
> - xcr0 = xcr;
> if (!(xcr0 & XSTATE_FP))
> return 1;
> if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
> @@ -599,6 +599,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
>
> kvm_put_guest_xcr0(vcpu);
> vcpu->arch.xcr0 = xcr0;
> +
> + if ((xcr0 ^ old_xcr0) & XSTATE_EXTEND_MASK)
> + kvm_update_cpuid(vcpu);
> return 0;
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
2014-01-22 10:21 ` Paolo Bonzini
@ 2014-01-22 10:31 ` H. Peter Anvin
0 siblings, 0 replies; 4+ messages in thread
From: H. Peter Anvin @ 2014-01-22 10:31 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Liu, Jinsong, gleb@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, Ren, Qiaowei
On 01/22/2014 02:21 AM, Paolo Bonzini wrote:
> Il 21/01/2014 19:59, Liu, Jinsong ha scritto:
>> From 3155a190ce6ebb213e6c724240f4e6620ba67a9d Mon Sep 17 00:00:00 2001
>> From: Liu Jinsong <jinsong.liu@intel.com>
>> Date: Fri, 13 Dec 2013 02:32:03 +0800
>> Subject: [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
>>
>> EBX of cpuid(0xD, 0) is dynamic per XCR0 features enable/disable.
>> Bit 63 of XCR0 is reserved for future expansion.
>>
>> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
>
> Peter, can I have your acked-by on this?
>
Yes.
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
2014-01-21 18:59 [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug Liu, Jinsong
2014-01-22 10:21 ` Paolo Bonzini
@ 2014-01-22 11:05 ` Paolo Bonzini
1 sibling, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2014-01-22 11:05 UTC (permalink / raw)
To: Liu, Jinsong
Cc: gleb@redhat.com, kvm@vger.kernel.org, qemu-devel@nongnu.org,
linux-kernel@vger.kernel.org, hpa@zytor.com, Ren, Qiaowei
Il 21/01/2014 19:59, Liu, Jinsong ha scritto:
> From 3155a190ce6ebb213e6c724240f4e6620ba67a9d Mon Sep 17 00:00:00 2001
> From: Liu Jinsong <jinsong.liu@intel.com>
> Date: Fri, 13 Dec 2013 02:32:03 +0800
> Subject: [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug
>
> EBX of cpuid(0xD, 0) is dynamic per XCR0 features enable/disable.
> Bit 63 of XCR0 is reserved for future expansion.
>
> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
> ---
> arch/x86/include/asm/xsave.h | 2 ++
> arch/x86/kvm/cpuid.c | 6 +++---
> arch/x86/kvm/x86.c | 7 +++++--
> 3 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
> index 5547389..f6c4e85 100644
> --- a/arch/x86/include/asm/xsave.h
> +++ b/arch/x86/include/asm/xsave.h
> @@ -13,6 +13,8 @@
> #define XSTATE_BNDCSR 0x10
>
> #define XSTATE_FPSSE (XSTATE_FP | XSTATE_SSE)
> +/* Bit 63 of XCR0 is reserved for future expansion */
> +#define XSTATE_EXTEND_MASK (~(XSTATE_FPSSE | (1 << 63)))
This should be 1ULL, not 1. The compiler should have warned you.
Paolo
>
> #define FXSAVE_SIZE 512
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index c697625..2d661e6 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -28,7 +28,7 @@ static u32 xstate_required_size(u64 xstate_bv)
> int feature_bit = 0;
> u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
>
> - xstate_bv &= ~XSTATE_FPSSE;
> + xstate_bv &= XSTATE_EXTEND_MASK;
> while (xstate_bv) {
> if (xstate_bv & 0x1) {
> u32 eax, ebx, ecx, edx;
> @@ -74,8 +74,8 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
> vcpu->arch.guest_supported_xcr0 =
> (best->eax | ((u64)best->edx << 32)) &
> host_xcr0 & KVM_SUPPORTED_XCR0;
> - vcpu->arch.guest_xstate_size =
> - xstate_required_size(vcpu->arch.guest_supported_xcr0);
> + vcpu->arch.guest_xstate_size = best->ebx =
> + xstate_required_size(vcpu->arch.xcr0);
> }
>
> kvm_pmu_cpuid_update(vcpu);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 21ef1ba..1657ca2 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -576,13 +576,13 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
>
> int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
> {
> - u64 xcr0;
> + u64 xcr0 = xcr;
> + u64 old_xcr0 = vcpu->arch.xcr0;
> u64 valid_bits;
>
> /* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */
> if (index != XCR_XFEATURE_ENABLED_MASK)
> return 1;
> - xcr0 = xcr;
> if (!(xcr0 & XSTATE_FP))
> return 1;
> if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
> @@ -599,6 +599,9 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
>
> kvm_put_guest_xcr0(vcpu);
> vcpu->arch.xcr0 = xcr0;
> +
> + if ((xcr0 ^ old_xcr0) & XSTATE_EXTEND_MASK)
> + kvm_update_cpuid(vcpu);
> return 0;
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-01-21 18:59 [Qemu-devel] [PATCH v3 1/4] KVM/X86: Fix xsave cpuid exposing bug Liu, Jinsong
2014-01-22 10:21 ` Paolo Bonzini
2014-01-22 10:31 ` H. Peter Anvin
2014-01-22 11:05 ` Paolo Bonzini
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