From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Yang Weijiang <weijiang.yang@intel.com>
Cc: pbonzini@redhat.com, rkrcmar@redhat.com,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
mst@redhat.com, yu-cheng.yu@intel.com, yi.z.zhang@intel.com,
hjl.tools@gmail.com, Zhang Yi Z <yi.z.zhang@linux.intel.com>
Subject: Re: [PATCH v1 7/8] kvm:cpuid Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1).
Date: Wed, 2 Jan 2019 10:54:53 -0800 [thread overview]
Message-ID: <20190102185449.GE7460@linux.intel.com> (raw)
In-Reply-To: <20181226081532.30698-8-weijiang.yang@intel.com>
On Wed, Dec 26, 2018 at 04:15:31PM +0800, Yang Weijiang wrote:
> According to latest Software Development Manual vol.2/3.2,
> for CPUID.(EAX=0xD,ECX=1), it should report xsaves area size
> containing all states enabled by XCR0|IA32_MSR_XSS.
>
> Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
> arch/x86/kvm/cpuid.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 5bac31e58955..55c282f71f93 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -121,7 +121,8 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
>
> best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
> if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
> - best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
> + best->ebx = xstate_required_size(vcpu->arch.xcr0 |
> + best->ecx | ((u64)best->edx << 32), true);
Passing the CPUID bits is wrong, it needs to be the guest's IA32_MSR_XSS.
The CPUID bits enumerate what is legal to enable, not what features are
actually enabled by software.
>
> /*
> * The existing code assumes virtual address is 48-bit or 57-bit in the
> --
> 2.17.1
>
next prev parent reply other threads:[~2019-01-02 18:54 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-26 8:15 [PATCH v1 0/8] This patch-set is to enable kvm Guest OS CET support Yang Weijiang
2018-12-26 8:15 ` [PATCH v1 1/8] kvm:vmx Introduce CET related VMCS field definitions Yang Weijiang
2019-01-02 18:09 ` Sean Christopherson
2018-12-26 8:15 ` [PATCH v1 2/8] kvm: Define CR4.CET[bit 23] (master enable bit) for guest OS Yang Weijiang
2018-12-26 8:15 ` [PATCH v1 3/8] kvm:vmx Enable loading CET state bit while guest CR4.CET is being set Yang Weijiang
2018-12-26 8:52 ` Liran Alon
2018-12-27 6:07 ` Yang,Weijiang
2018-12-26 8:15 ` [PATCH v1 4/8] kvm:vmx Pass through host CET related MSRs to Guest Yang Weijiang
2019-01-02 18:18 ` Sean Christopherson
2019-01-02 19:12 ` Jim Mattson
2018-12-26 8:15 ` [PATCH v1 5/8] kvm:x86 Enable MSR_IA32_XSS bit 11 and 12 for CET xsaves/xrstors Yang Weijiang
2019-01-02 18:24 ` Sean Christopherson
2019-01-02 19:19 ` Jim Mattson
2019-01-06 21:17 ` Yang Weijiang
2018-12-26 8:15 ` [PATCH v1 6/8] kvm:cpuid Add CPUID support for CET xsaves component query Yang Weijiang
2019-01-02 18:49 ` Sean Christopherson
2018-12-26 8:15 ` [PATCH v1 7/8] kvm:cpuid Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1) Yang Weijiang
2019-01-02 18:54 ` Sean Christopherson [this message]
2018-12-26 8:15 ` [PATCH v1 8/8] kvm:cpuid Report CET SHSTK and IBT support in CPUID.(EAX=0x7,ECX=0) Yang Weijiang
2019-01-02 19:00 ` Sean Christopherson
2019-01-07 16:03 ` Paolo Bonzini
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