linux-kernel - [PATCH v3 3/3] x86/kvm: Expose AMD Core Perf Extension flag to guests

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Message-Id: <e17325ceb5455d993064524048d26a7de126a967.1512771422.git.Janakarajan.Natarajan@amd.com>
Date:   Fri,  8 Dec 2017 16:39:14 -0600
From:   Janakarajan Natarajan <Janakarajan.Natarajan@....com>
To:     kvm@...r.kernel.org, x86@...nel.org, linux-kernel@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krcmar <rkrcmar@...hat.com>,
        Len Brown <len.brown@...el.com>, Kyle Huey <me@...ehuey.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Borislav Petkov <bp@...e.de>,
        Grzegorz Andrejczuk <grzegorz.andrejczuk@...el.com>,
        Kan Liang <Kan.liang@...el.com>,
        Janakarajan Natarajan <Janakarajan.Natarajan@....com>
Subject: [PATCH v3 3/3] x86/kvm: Expose AMD Core Perf Extension flag to guests

Expose the AMD Core Perf Extension flag to the guests.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@....com>
---
 arch/x86/kvm/cpuid.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0099e10..8c95a7c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -55,6 +55,11 @@ bool kvm_mpx_supported(void)
 }
 EXPORT_SYMBOL_GPL(kvm_mpx_supported);
 
+bool perf_ext_supported(void)
+{
+	return boot_cpu_has(X86_FEATURE_PERFCTR_CORE);
+}
+
 u64 kvm_supported_xcr0(void)
 {
 	u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
@@ -327,6 +332,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
 	unsigned f_mpx = kvm_mpx_supported() ? F(MPX) : 0;
 	unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
+	unsigned f_perfext = perf_ext_supported() ? F(PERFCTR_CORE) : 0;
 
 	/* cpuid 1.edx */
 	const u32 kvm_cpuid_1_edx_x86_features =
@@ -365,7 +371,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
 		F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
-		0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
+		0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM) | f_perfext;
 
 	/* cpuid 0xC0000001.edx */
 	const u32 kvm_cpuid_C000_0001_edx_x86_features =
-- 
2.7.4