From: Jing Liu <jing2.liu@intel.com>
To: x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
pbonzini@redhat.com
Cc: seanjc@google.com, jun.nakajima@intel.com, kevin.tian@intel.com,
jing2.liu@linux.intel.com, jing2.liu@intel.com,
guang.zeng@intel.com, wei.w.wang@intel.com, yang.zhong@intel.com
Subject: [PATCH v2 09/23] kvm: x86: Enable dynamic XSAVE features at KVM_SET_CPUID2
Date: Fri, 17 Dec 2021 07:29:49 -0800 [thread overview]
Message-ID: <20211217153003.1719189-10-jing2.liu@intel.com> (raw)
In-Reply-To: <20211217153003.1719189-1-jing2.liu@intel.com>
Statically enable all xfeatures allowed by guest perm in
KVM_SET_CPUID2, with fpstate buffer sized accordingly. This avoids
run-time expansion in the emulation and restore path of XCR0 and
XFD MSR [1].
Change kvm_vcpu_after_set_cpuid() to return error given fpstate
reallocation may fail.
[1] https://lore.kernel.org/all/20211214024948.048572883@linutronix.de/
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
---
arch/x86/kvm/cpuid.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a068373a7fbd..eb5a5070accb 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -204,10 +204,12 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime);
-static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
+static int kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
struct kvm_cpuid_entry2 *best;
+ u64 xfeatures;
+ int r;
best = kvm_find_cpuid_entry(vcpu, 1, 0);
if (best && apic) {
@@ -222,9 +224,17 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
if (!best)
vcpu->arch.guest_supported_xcr0 = 0;
- else
- vcpu->arch.guest_supported_xcr0 =
- (best->eax | ((u64)best->edx << 32)) & supported_xcr0;
+ else {
+ xfeatures = best->eax | ((u64)best->edx << 32);
+
+ vcpu->arch.guest_supported_xcr0 = xfeatures & supported_xcr0;
+
+ if (xfeatures != vcpu->arch.guest_fpu.xfeatures) {
+ r = fpu_update_guest_perm_features(&vcpu->arch.guest_fpu);
+ if (r)
+ return r;
+ }
+ }
/*
* Bits 127:0 of the allowed SECS.ATTRIBUTES (CPUID.0x12.0x1) enumerate
@@ -260,6 +270,8 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
* adjustments to the reserved GPA bits.
*/
kvm_mmu_after_set_cpuid(vcpu);
+
+ return 0;
}
int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
@@ -301,9 +313,7 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
kvm_update_kvm_cpuid_base(vcpu);
kvm_update_cpuid_runtime(vcpu);
- kvm_vcpu_after_set_cpuid(vcpu);
-
- return 0;
+ return kvm_vcpu_after_set_cpuid(vcpu);
}
/* when an old userspace process fills a new kernel module */
--
2.27.0
next prev parent reply other threads:[~2021-12-17 15:30 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 15:29 [PATCH v2 00/23] AMX Support in KVM Jing Liu
2021-12-17 15:29 ` [PATCH v2 01/23] x86/fpu: Extend fpu_xstate_prctl() with guest permissions Jing Liu
2021-12-17 18:45 ` Thomas Gleixner
2021-12-17 18:47 ` Thomas Gleixner
2021-12-17 15:29 ` [PATCH v2 02/23] x86/fpu: Prepare guest FPU for dynamically enabled FPU features Jing Liu
2021-12-17 15:29 ` [PATCH v2 03/23] kvm: x86: Fix xstate_required_size() to follow XSTATE alignment rule Jing Liu
2021-12-17 15:29 ` [PATCH v2 04/23] kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID Jing Liu
2021-12-20 13:20 ` Paolo Bonzini
2021-12-17 15:29 ` [PATCH v2 05/23] kvm: x86: Check permitted dynamic xfeatures at KVM_SET_CPUID2 Jing Liu
2021-12-17 15:29 ` [PATCH v2 06/23] x86/fpu: Make XFD initialization in __fpstate_reset() a function argument Jing Liu
2021-12-17 15:29 ` [PATCH v2 07/23] x86/fpu: Add guest support to xfd_enable_feature() Jing Liu
2021-12-17 15:29 ` [PATCH v2 08/23] x86/fpu: Provide fpu_update_guest_perm_features() for guest Jing Liu
2021-12-17 18:50 ` Thomas Gleixner
2021-12-17 15:29 ` Jing Liu [this message]
2021-12-17 15:29 ` [PATCH v2 10/23] x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation Jing Liu
2021-12-17 15:29 ` [PATCH v2 11/23] kvm: x86: Add emulation for IA32_XFD Jing Liu
2021-12-17 15:29 ` [PATCH v2 12/23] x86/fpu: Prepare xfd_err in struct fpu_guest Jing Liu
2021-12-17 15:29 ` [PATCH v2 13/23] kvm: x86: Intercept #NM for saving IA32_XFD_ERR Jing Liu
2021-12-17 15:29 ` [PATCH v2 14/23] kvm: x86: Emulate IA32_XFD_ERR for guest Jing Liu
2021-12-17 15:29 ` [PATCH v2 15/23] kvm: x86: Add XCR0 support for Intel AMX Jing Liu
2021-12-17 15:29 ` [PATCH v2 16/23] kvm: x86: Add CPUID " Jing Liu
2021-12-17 15:29 ` [PATCH v2 17/23] x86/fpu: add uabi_size to guest_fpu Jing Liu
2021-12-17 15:29 ` [PATCH v2 18/23] kvm: x86: Get/set expanded xstate buffer Jing Liu
2021-12-20 9:04 ` Paolo Bonzini
2021-12-21 2:45 ` Wang, Wei W
2021-12-21 8:45 ` Paolo Bonzini
2021-12-21 9:06 ` Wang, Wei W
2021-12-21 9:30 ` Paolo Bonzini
2021-12-17 15:29 ` [PATCH v2 19/23] kvm: selftests: Add support for KVM_CAP_XSAVE2 Jing Liu
2021-12-20 13:19 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 20/23] docs: kvm: Add KVM_GET_XSAVE2 Jing Liu
2021-12-20 9:04 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 21/23] x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() Jing Liu
2021-12-17 15:30 ` [PATCH v2 22/23] kvm: x86: Disable interception for IA32_XFD on demand Jing Liu
2021-12-20 9:07 ` Paolo Bonzini
2021-12-21 6:42 ` Liu, Jing2
2021-12-21 8:46 ` Paolo Bonzini
2021-12-17 15:30 ` [PATCH v2 23/23] kvm: x86: Disable RDMSR interception of IA32_XFD_ERR Jing Liu
2021-12-20 9:08 ` Paolo Bonzini
2021-12-21 6:29 ` Liu, Jing2
2021-12-21 8:48 ` Paolo Bonzini
2021-12-21 9:00 ` Liu, Jing2
2021-12-21 9:05 ` Paolo Bonzini
2021-12-17 18:52 ` [PATCH v2 00/23] AMX Support in KVM Thomas Gleixner
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