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: [RESEND v13 05/11] KVM: x86: Refresh CPUID once guest changes XSS bits
Date: Thu, 16 Jul 2020 11:16:21 +0800 [thread overview]
Message-ID: <20200716031627.11492-6-weijiang.yang@intel.com> (raw)
In-Reply-To: <20200716031627.11492-1-weijiang.yang@intel.com>
CPUID(0xd, 1) reports the current required storage size of XCR0 | XSS,
when guest updates the XSS, it's necessary to update the CPUID leaf, otherwise
guest will fetch old state size, and results to some WARN traces during guest
running.
supported_xss is initialized to host_xss & KVM_SUPPORTED_XSS to indicate current
MSR_IA32_XSS bits supported in KVM, but actual XSS bits seen in guest depends
on the setting of CPUID(0xd,1).{ECX, EDX} for guest.
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 | 23 +++++++++++++++++++----
arch/x86/kvm/x86.c | 12 ++++++++----
3 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index be5363b21540..e8c749596ba2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -654,6 +654,7 @@ 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 8a294f9747aa..d97b2a6e8a8c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -88,14 +88,29 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
vcpu->arch.guest_supported_xcr0 = 0;
} else {
vcpu->arch.guest_supported_xcr0 =
- (best->eax | ((u64)best->edx << 32)) & supported_xcr0;
+ (((u64)best->edx << 32) | best->eax) & supported_xcr0;
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;
+ }
/*
* The existing code assumes virtual address is 48-bit or 57-bit in the
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 906e07039d59..8aed32ff9c0c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2912,9 +2912,12 @@ 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(vcpu);
+ }
break;
case MSR_SMI_COUNT:
if (!msr_info->host_initiated)
@@ -9779,8 +9782,9 @@ int kvm_arch_hardware_setup(void *opaque)
memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
- if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
- supported_xss = 0;
+ supported_xss = 0;
+ if (kvm_cpu_cap_has(X86_FEATURE_XSAVES))
+ supported_xss = host_xss & KVM_SUPPORTED_XSS;
#define __kvm_cpu_cap_has(UNUSED_, f) kvm_cpu_cap_has(f)
cr4_reserved_bits = __cr4_reserved_bits(__kvm_cpu_cap_has, UNUSED_);
--
2.17.2
next prev parent reply other threads:[~2020-07-16 3:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 3:16 [RESEND PATCH v13 00/11] Introduce support for guest CET feature Yang Weijiang
2020-07-16 3:16 ` [RESEND v13 01/11] KVM: x86: Include CET definitions for KVM test purpose Yang Weijiang
2020-07-16 3:16 ` [RESEND v13 02/11] KVM: VMX: Introduce CET VMCS fields and flags Yang Weijiang
2020-07-22 19:48 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 03/11] KVM: VMX: Set guest CET MSRs per KVM and host configuration Yang Weijiang
2020-07-22 20:14 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 04/11] KVM: VMX: Configure CET settings upon guest CR0/4 changing Yang Weijiang
2020-07-22 20:31 ` Sean Christopherson
2020-07-16 3:16 ` Yang Weijiang [this message]
2020-07-22 20:32 ` [RESEND v13 05/11] KVM: x86: Refresh CPUID once guest changes XSS bits Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 06/11] KVM: x86: Load guest fpu state when access MSRs managed by XSAVES Yang Weijiang
2020-07-22 20:32 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 07/11] KVM: x86: Add userspace access interface for CET MSRs Yang Weijiang
2020-07-22 20:54 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 08/11] KVM: VMX: Enable CET support for nested VM Yang Weijiang
2020-07-22 21:20 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 09/11] KVM: VMX: Add VMCS dump and sanity check for CET states Yang Weijiang
2020-07-22 21:29 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 10/11] KVM: x86: Add #CP support in guest exception dispatch Yang Weijiang
2020-07-22 21:29 ` Sean Christopherson
2020-07-16 3:16 ` [RESEND v13 11/11] KVM: x86: Enable CET virtualization and advertise CET to userspace Yang Weijiang
2020-07-22 21:33 ` Sean Christopherson
2020-07-22 19:48 ` [RESEND PATCH v13 00/11] Introduce support for guest CET feature Sean Christopherson
2020-07-23 3:17 ` Yang Weijiang
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