linux-kernel - [PATCH v2 50/66] KVM: x86: Override host CPUID results with kvm_cpu

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]

Date:   Mon,  2 Mar 2020 15:56:53 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [PATCH v2 50/66] KVM: x86: Override host CPUID results with kvm_cpu_caps

Override CPUID entries with kvm_cpu_caps during KVM_GET_SUPPORTED_CPUID
instead of masking the host CPUID result, which is redundant now that
the host CPUID is incorporated into kvm_cpu_caps at runtime.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/cpuid.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ec8e24b1c1a7..5fef02dbf4e1 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -261,13 +261,13 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 	return r;
 }
 
-static __always_inline void cpuid_entry_mask(struct kvm_cpuid_entry2 *entry,
-					     enum cpuid_leafs leaf)
+static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry,
+						 enum cpuid_leafs leaf)
 {
 	u32 *reg = cpuid_entry_get_reg(entry, leaf * 32);
 
 	BUILD_BUG_ON(leaf >= ARRAY_SIZE(kvm_cpu_caps));
-	*reg &= kvm_cpu_caps[leaf];
+	*reg = kvm_cpu_caps[leaf];
 }
 
 static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask)
@@ -490,8 +490,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0x1fU);
 		break;
 	case 1:
-		cpuid_entry_mask(entry, CPUID_1_EDX);
-		cpuid_entry_mask(entry, CPUID_1_ECX);
+		cpuid_entry_override(entry, CPUID_1_EDX);
+		cpuid_entry_override(entry, CPUID_1_ECX);
 		/* we support x2apic emulation even if host does not support
 		 * it since we emulate x2apic in software */
 		cpuid_entry_set(entry, X86_FEATURE_X2APIC);
@@ -536,9 +536,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	/* function 7 has additional index. */
 	case 7:
 		entry->eax = min(entry->eax, 1u);
-		cpuid_entry_mask(entry, CPUID_7_0_EBX);
-		cpuid_entry_mask(entry, CPUID_7_ECX);
-		cpuid_entry_mask(entry, CPUID_7_EDX);
+		cpuid_entry_override(entry, CPUID_7_0_EBX);
+		cpuid_entry_override(entry, CPUID_7_ECX);
+		cpuid_entry_override(entry, CPUID_7_EDX);
 
 		/* TSC_ADJUST and ARCH_CAPABILITIES are emulated in software. */
 		cpuid_entry_set(entry, X86_FEATURE_TSC_ADJUST);
@@ -557,7 +557,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			if (!entry)
 				goto out;
 
-			cpuid_entry_mask(entry, CPUID_7_1_EAX);
+			cpuid_entry_override(entry, CPUID_7_1_EAX);
 			entry->ebx = 0;
 			entry->ecx = 0;
 			entry->edx = 0;
@@ -623,7 +623,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		if (!entry)
 			goto out;
 
-		cpuid_entry_mask(entry, CPUID_D_1_EAX);
+		cpuid_entry_override(entry, CPUID_D_1_EAX);
 		if (entry->eax & (F(XSAVES)|F(XSAVEC)))
 			entry->ebx = xstate_required_size(supported_xcr0, true);
 		else
@@ -702,8 +702,8 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0x8000001f);
 		break;
 	case 0x80000001:
-		cpuid_entry_mask(entry, CPUID_8000_0001_EDX);
-		cpuid_entry_mask(entry, CPUID_8000_0001_ECX);
+		cpuid_entry_override(entry, CPUID_8000_0001_EDX);
+		cpuid_entry_override(entry, CPUID_8000_0001_ECX);
 		break;
 	case 0x80000007: /* Advanced power management */
 		/* invariant TSC is CPUID.80000007H:EDX[8] */
@@ -721,7 +721,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			g_phys_as = phys_as;
 		entry->eax = g_phys_as | (virt_as << 8);
 		entry->edx = 0;
-		cpuid_entry_mask(entry, CPUID_8000_0008_EBX);
+		cpuid_entry_override(entry, CPUID_8000_0008_EBX);
 		/*
 		 * AMD has separate bits for each SPEC_CTRL bit.
 		 * arch/x86/kernel/cpu/bugs.c is kind enough to
@@ -763,7 +763,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		entry->eax = min(entry->eax, 0xC0000004);
 		break;
 	case 0xC0000001:
-		cpuid_entry_mask(entry, CPUID_C000_0001_EDX);
+		cpuid_entry_override(entry, CPUID_C000_0001_EDX);
 		break;
 	case 3: /* Processor serial number */
 	case 5: /* MONITOR/MWAIT */
-- 
2.24.1