From: Yang Weijiang <weijiang.yang@intel.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
pbonzini@redhat.com, sean.j.christopherson@intel.com,
jmattson@google.com
Cc: yu.c.zhang@linux.intel.com, Yang Weijiang <weijiang.yang@intel.com>
Subject: [PATCH v14 02/13] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS
Date: Fri, 6 Nov 2020 09:16:26 +0800 [thread overview]
Message-ID: <20201106011637.14289-3-weijiang.yang@intel.com> (raw)
In-Reply-To: <20201106011637.14289-1-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 d44858b69353..1620a2cca781 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 06a278b3701d..2c737337f466 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -115,9 +115,24 @@ 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 fce18a2537ea..0823bf1e2977 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3124,9 +3124,12 @@ 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)
--
2.17.2
next prev parent reply other threads:[~2020-11-06 1:07 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-06 1:16 [PATCH v14 00/13] Introduce support for guest CET feature Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 01/13] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2020-11-06 1:16 ` Yang Weijiang [this message]
2020-11-06 1:16 ` [PATCH v14 03/13] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 04/13] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 05/13] KVM: x86: Add fault checks for CR4.CET Yang Weijiang
2020-11-09 10:44 ` kernel test robot
2020-11-06 1:16 ` [PATCH v14 06/13] KVM: x86: Load guest fpu state when accessing MSRs managed by XSAVES Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 07/13] KVM: VMX: Emulate reads and writes to CET MSRs Yang Weijiang
2021-01-28 17:45 ` Paolo Bonzini
2021-01-29 8:07 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 08/13] KVM: VMX: Add a synthetic MSR to allow userspace VMM to access GUEST_SSP Yang Weijiang
2021-01-28 17:41 ` Paolo Bonzini
2021-01-28 17:42 ` Paolo Bonzini
2020-11-06 1:16 ` [PATCH v14 09/13] KVM: x86: Report CET MSRs as to-be-saved if CET is supported Yang Weijiang
2021-01-28 17:46 ` Paolo Bonzini
2021-01-29 8:08 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 10/13] KVM: x86: Enable CET virtualization for VMX and advertise CET to userspace Yang Weijiang
2020-11-09 7:23 ` kernel test robot
2021-01-28 17:53 ` Paolo Bonzini
[not found] ` <20210129112437.GA29715@local-michael-cet-test.sh.intel.com>
[not found] ` <68e288ee-6e09-36f1-a6c9-bed864eb7678@redhat.com>
[not found] ` <20210129121717.GA30243@local-michael-cet-test.sh.intel.com>
[not found] ` <1cf7e501-2c69-8b76-9332-42db1348ab08@redhat.com>
2021-01-30 6:32 ` Yang Weijiang
2021-02-01 4:56 ` Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 11/13] KVM: VMX: Pass through CET MSRs to the guest when supported Yang Weijiang
2021-01-28 17:54 ` Paolo Bonzini
2021-01-28 18:04 ` Paolo Bonzini
2020-11-06 1:16 ` [PATCH v14 12/13] KVM: nVMX: Add helper to check the vmcs01 MSR bitmap for MSR pass-through Yang Weijiang
2020-11-06 1:16 ` [PATCH v14 13/13] KVM: nVMX: Enable CET support for nested VMX Yang Weijiang
2021-01-28 17:57 ` [PATCH v14 00/13] Introduce support for guest CET feature Paolo Bonzini
2021-01-28 18:04 ` Sean Christopherson
2021-01-28 18:06 ` Paolo Bonzini
2021-01-28 18:24 ` Sean Christopherson
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