From: Yang Weijiang <weijiang.yang@intel.com>
To: pbonzini@redhat.com, seanjc@google.com, jmattson@google.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: yu.c.zhang@linux.intel.com, Yang Weijiang <weijiang.yang@intel.com>
Subject: [PATCH v15 02/14] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS
Date: Wed, 3 Feb 2021 19:34:09 +0800 [thread overview]
Message-ID: <20210203113421.5759-3-weijiang.yang@intel.com> (raw)
In-Reply-To: <20210203113421.5759-1-weijiang.yang@intel.com>
Updated CPUID.0xD.0x1, which reports the current required storage size
of all features enabled via XCR0 | XSS, when the guest's XSS is modified.
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/include/asm/kvm_host.h | 1 +
arch/x86/kvm/cpuid.c | 21 ++++++++++++++++++---
arch/x86/kvm/x86.c | 7 +++++--
3 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3d6616f6f6ef..1734f872712d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -611,6 +611,7 @@ struct kvm_vcpu_arch {
u64 xcr0;
u64 guest_supported_xcr0;
+ u64 guest_supported_xss;
struct kvm_pio_request pio;
void *pio_data;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 13036cf0b912..6d7d9d59fd5b 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -129,9 +129,24 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
best->ebx = xstate_required_size(vcpu->arch.xcr0, false);
best = kvm_find_cpuid_entry(vcpu, 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)) {
+ u64 xstate = vcpu->arch.xcr0 | vcpu->arch.ia32_xss;
+
+ best->ebx = xstate_required_size(xstate, true);
+ }
+
+ if (!cpuid_entry_has(best, X86_FEATURE_XSAVES)) {
+ best->ecx = 0;
+ best->edx = 0;
+ }
+ vcpu->arch.guest_supported_xss =
+ (((u64)best->edx << 32) | best->ecx) & supported_xss;
+
+ } else {
+ vcpu->arch.guest_supported_xss = 0;
+ }
best = kvm_find_cpuid_entry(vcpu, KVM_CPUID_FEATURES, 0);
if (kvm_hlt_in_guest(vcpu->kvm) && best &&
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a657706358e8..30a07caf077c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3133,9 +3133,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
* IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than
* XSAVES/XRSTORS to save/restore PT MSRs.
*/
- if (data & ~supported_xss)
+ if (data & ~vcpu->arch.guest_supported_xss)
return 1;
- vcpu->arch.ia32_xss = data;
+ 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)
--
2.26.2
next prev parent reply other threads:[~2021-02-03 11:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 11:34 [PATCH v15 00/14] Introduce support for guest CET feature Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 01/14] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2021-02-03 11:34 ` Yang Weijiang [this message]
2021-02-03 11:34 ` [PATCH v15 03/14] KVM: x86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 04/14] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2021-02-03 21:46 ` Sean Christopherson
2021-02-04 7:22 ` Yang Weijiang
2021-02-04 8:28 ` Paolo Bonzini
2021-02-04 8:24 ` Paolo Bonzini
2021-02-04 16:42 ` Sean Christopherson
2021-02-04 17:29 ` Paolo Bonzini
2021-02-03 11:34 ` [PATCH v15 05/14] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 06/14] KVM: x86: Add fault checks for CR4.CET Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 07/14] KVM: VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2021-02-03 11:57 ` Paolo Bonzini
2021-02-03 12:50 ` Yang Weijiang
2022-05-18 15:55 ` John Allen
2022-05-18 16:16 ` Sean Christopherson
2022-05-19 8:49 ` Yang, Weijiang
2021-02-03 11:34 ` [PATCH v15 08/14] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 09/14] KVM: x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 10/14] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 11/14] KVM: VMX: Pass through CET MSRs to the guest when supported Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 12/14] KVM: nVMX: Add helper to check the vmcs01 MSR bitmap for MSR pass-through Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 13/14] KVM: nVMX: Enable CET support for nested VMX Yang Weijiang
2021-02-03 11:34 ` [PATCH v15 14/14] KVM: x86: Save/Restore GUEST_SSP to/from SMRAM Yang Weijiang
2021-02-03 12:07 ` Paolo Bonzini
2021-02-03 12:59 ` Yang Weijiang
2021-02-03 12:40 ` [PATCH v15 00/14] Introduce support for guest CET feature Paolo Bonzini
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