linux-kernel - [PATCH v5 05/19] KVM:x86: Initialize kvm_caps.supported

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230803042732.88515-6-weijiang.yang@intel.com>
Date:   Thu,  3 Aug 2023 00:27:18 -0400
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     seanjc@...gle.com, pbonzini@...hat.com, peterz@...radead.org,
        john.allen@....com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     rick.p.edgecombe@...el.com, chao.gao@...el.com,
        binbin.wu@...ux.intel.com, weijiang.yang@...el.com
Subject: [PATCH v5 05/19] KVM:x86: Initialize kvm_caps.supported_xss

Set kvm_caps.supported_xss to host_xss && KVM XSS mask.
host_xss contains the host supported xstate feature bits for thread
context switch, KVM_SUPPORTED_XSS includes all KVM enabled XSS feature
bits, the operation result represents all KVM supported feature bits.
Since the result is subset of host_xss, the related XSAVE-managed MSRs
are automatically swapped for guest and host when vCPU exits to
userspace.

Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
---
 arch/x86/kvm/vmx/vmx.c | 1 -
 arch/x86/kvm/x86.c     | 6 +++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 0ecf4be2c6af..c8d9870cfecb 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7849,7 +7849,6 @@ static __init void vmx_set_cpu_caps(void)
 		kvm_cpu_cap_set(X86_FEATURE_UMIP);
 
 	/* CPUID 0xD.1 */
-	kvm_caps.supported_xss = 0;
 	if (!cpu_has_vmx_xsaves())
 		kvm_cpu_cap_clear(X86_FEATURE_XSAVES);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5d6d6fa33e5b..e9f3627d5fdd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -225,6 +225,8 @@ static struct kvm_user_return_msrs __percpu *user_return_msrs;
 				| XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
 				| XFEATURE_MASK_PKRU | XFEATURE_MASK_XTILE)
 
+#define KVM_SUPPORTED_XSS     0
+
 u64 __read_mostly host_efer;
 EXPORT_SYMBOL_GPL(host_efer);
 
@@ -9498,8 +9500,10 @@ static int __kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 
 	rdmsrl_safe(MSR_EFER, &host_efer);
 
-	if (boot_cpu_has(X86_FEATURE_XSAVES))
+	if (boot_cpu_has(X86_FEATURE_XSAVES)) {
 		rdmsrl(MSR_IA32_XSS, host_xss);
+		kvm_caps.supported_xss = host_xss & KVM_SUPPORTED_XSS;
+	}
 
 	kvm_init_pmu_capability(ops->pmu_ops);
 
-- 
2.27.0