From: Binbin Wu <binbin.wu@linux.intel.com>
To: Yang Weijiang <weijiang.yang@intel.com>,
seanjc@google.com, pbonzini@redhat.com, peterz@infradead.org,
john.allen@amd.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: rick.p.edgecombe@intel.com, Zhang Yi Z <yi.z.zhang@linux.intel.com>
Subject: Re: [PATCH v2 07/21] KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS
Date: Mon, 24 Apr 2023 09:38:59 +0800 [thread overview]
Message-ID: <85f9bf76-05ec-8948-4ef1-42a57d641766@linux.intel.com> (raw)
In-Reply-To: <20230421134615.62539-8-weijiang.yang@intel.com>
On 4/21/2023 9:46 PM, Yang Weijiang wrote:
> Update CPUID(EAX=0DH,ECX=1) when the guest's XSS is modified.
> CPUID(EAX=0DH,ECX=1).EBX reports current required storage size for all
> features enabled via XCR0 | XSS so that guest can allocate correct xsave
> buffer.
>
> Note, KVM does not yet support any XSS based features, i.e. supported_xss
> is guaranteed to be zero at this time.
>
> Co-developed-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
> 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 | 11 ++++++++---
> arch/x86/kvm/x86.c | 6 ++++--
> 2 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 123bf8b97a4b..dd6d5150d86a 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -276,9 +276,14 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e
> best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
>
> best = cpuid_entry2_find(entries, nent, 0xD, 1);
> - if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
> - cpuid_entry_has(best, X86_FEATURE_XSAVEC)))
> - best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
> + if (best) {
> + if (cpuid_entry_has(best, X86_FEATURE_XSAVES) ||
> + cpuid_entry_has(best, X86_FEATURE_XSAVEC)) {
Is it necessary to change to use two ifs?
> + u64 xstate = vcpu->arch.xcr0 | vcpu->arch.ia32_xss;
> +
> + best->ebx = xstate_required_size(xstate, true);
> + }
> + }
>
> best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent);
> if (kvm_hlt_in_guest(vcpu->kvm) && best &&
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 33a780fe820b..ab3360a10933 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3776,8 +3776,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> */
> if (data & ~kvm_caps.supported_xss)
> return 1;
> - vcpu->arch.ia32_xss = data;
> - kvm_update_cpuid_runtime(vcpu);
> + if (vcpu->arch.ia32_xss != data) {
> + vcpu->arch.ia32_xss = data;
> + kvm_update_cpuid_runtime(vcpu);
> + }
> break;
> case MSR_SMI_COUNT:
> if (!msr_info->host_initiated)
next prev parent reply other threads:[~2023-04-24 1:39 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 13:45 [PATCH v2 00/21] Enable CET Virtualization Yang Weijiang
2023-04-21 13:45 ` [PATCH v2 01/21] x86/shstk: Add Kconfig option for shadow stack Yang Weijiang
2023-04-21 13:45 ` [PATCH v2 02/21] x86/cpufeatures: Add CPU feature flags for shadow stacks Yang Weijiang
2023-04-21 13:45 ` [PATCH v2 03/21] x86/cpufeatures: Enable CET CR4 bit for shadow stack Yang Weijiang
2023-04-21 13:45 ` [PATCH v2 04/21] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yang Weijiang
2023-04-21 13:45 ` [PATCH v2 05/21] x86/fpu: Add helper for modifying xstate Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 06/21] KVM:x86: Report XSS as to-be-saved if there are supported features Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 07/21] KVM:x86: Refresh CPUID on write to guest MSR_IA32_XSS Yang Weijiang
2023-04-24 1:38 ` Binbin Wu [this message]
2023-04-24 6:15 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 08/21] KVM:x86: Init kvm_caps.supported_xss with supported feature bits Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 09/21] KVM:x86: Load guest FPU state when accessing xsaves-managed MSRs Yang Weijiang
2023-04-27 3:46 ` Binbin Wu
2023-04-27 15:57 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 10/21] KVM:x86: Add #CP support in guest exception classification Yang Weijiang
2023-04-28 6:09 ` Binbin Wu
2023-05-04 3:41 ` Yang, Weijiang
2023-05-04 5:36 ` Binbin Wu
2023-05-04 6:59 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 11/21] KVM:VMX: Introduce CET VMCS fields and control bits Yang Weijiang
2023-05-05 2:18 ` Binbin Wu
2023-05-05 2:22 ` Binbin Wu
2023-05-05 7:07 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 12/21] KVM:x86: Add fault checks for guest CR4.CET setting Yang Weijiang
2023-05-05 5:01 ` Binbin Wu
2023-05-05 7:24 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 13/21] KVM:VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 14/21] KVM:VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2023-05-03 17:08 ` Edgecombe, Rick P
2023-05-04 1:30 ` Yang, Weijiang
2023-04-21 13:46 ` [PATCH v2 15/21] KVM:x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 16/21] KVM:x86: Save/Restore GUEST_SSP to/from SMM state save area Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 17/21] KVM:VMX: Pass through user CET MSRs to the guest Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 18/21] KVM:x86: Enable CET virtualization for VMX and advertise to userspace Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 19/21] KVM:nVMX: Enable user CET support for nested VMX Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 20/21] KVM:x86: Enable supervisor IBT support for guest Yang Weijiang
2023-04-21 13:46 ` [PATCH v2 21/21] KVM:x86: Support CET supervisor shadow stack MSR access Yang Weijiang
2023-05-03 17:06 ` Edgecombe, Rick P
2023-05-04 1:11 ` Yang, Weijiang
2023-05-03 17:07 ` Edgecombe, Rick P
2023-05-04 1:20 ` Yang, Weijiang
2023-05-04 4:17 ` Edgecombe, Rick P
2023-05-04 6:51 ` Yang, Weijiang
2023-04-21 21:54 ` [PATCH v2 00/21] Enable CET Virtualization Mike Rapoport
2023-04-23 5:37 ` Yang, Weijiang
2023-04-24 18:22 ` John Allen
2023-04-22 13:02 ` Peter Zijlstra
2023-04-23 6:12 ` Yang, Weijiang
2023-04-23 8:30 ` Binbin Wu
2023-04-24 6:12 ` Yang, Weijiang
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