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AJvYcCW26f1SfUIEcEUBKaE0sGO5+AeBkvONOhJRlF6u29U8yWheKlHjughNDlVsh17ATr/E414CDvSHq0OXJ3Hv0LvIwJTMwzs3RUpkntwF X-Gm-Message-State: AOJu0YylwMacA58DMOUTaxOLFFZPPn7ysJxrkH8jKLUOJe828eNvgdWX tXPtGzEwQA9Ku35VNYMcegrbUdea/CyvK/gOqWaG6IPgorZQ62wA+sj63HIM4Dq+y42gqPGWgxM Tag== X-Google-Smtp-Source: AGHT+IEk/qagQm+PPoKBgAq1/IZEHMXRJTtdyHcj3BaOnR/XnjzjVOfM2KhbJnFogRXhtaCmRNAUu5C1hbM= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:f18b:b0:2c6:d13f:3f9e with SMTP id 98e67ed59e1d1-2ca3a7abd45mr10383a91.1.1720478179380; Mon, 08 Jul 2024 15:36:19 -0700 (PDT) Date: Mon, 8 Jul 2024 15:36:17 -0700 In-Reply-To: <2a4052ba67970ce41e79deb0a0931bb54e2c2a86.camel@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240517173926.965351-1-seanjc@google.com> <20240517173926.965351-20-seanjc@google.com> <2a4052ba67970ce41e79deb0a0931bb54e2c2a86.camel@redhat.com> Message-ID: Subject: Re: [PATCH v2 19/49] KVM: x86: Add a macro to init CPUID features that ignore host kernel support From: Sean Christopherson To: Maxim Levitsky Cc: Paolo Bonzini , Vitaly Kuznetsov , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Hou Wenlong , Kechen Lu , Oliver Upton , Binbin Wu , Yang Weijiang , Robert Hoo Content-Type: text/plain; charset="us-ascii" On Thu, Jul 04, 2024, Maxim Levitsky wrote: > On Fri, 2024-05-17 at 10:38 -0700, Sean Christopherson wrote: > > +/* > > + * Raw Feature - For features that KVM supports based purely on raw host CPUID, > > + * i.e. that KVM virtualizes even if the host kernel doesn't use the feature. > > + * Simply force set the feature in KVM's capabilities, raw CPUID support will > > + * be factored in by kvm_cpu_cap_mask(). > > + */ > > +#define RAW_F(name) \ > > +({ \ > > + kvm_cpu_cap_set(X86_FEATURE_##name); \ > > + F(name); \ > > +}) > > + > > /* > > * Magic value used by KVM when querying userspace-provided CPUID entries and > > * doesn't care about the CPIUD index because the index of the function in > > @@ -682,15 +694,12 @@ void kvm_set_cpu_caps(void) > > F(AVX512VL)); > > > > kvm_cpu_cap_mask(CPUID_7_ECX, > > - F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) | > > + F(AVX512VBMI) | RAW_F(LA57) | F(PKU) | 0 /*OSPKE*/ | F(RDPID) | > > F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) | > > F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) | > > F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ | > > F(SGX_LC) | F(BUS_LOCK_DETECT) > > ); > > - /* Set LA57 based on hardware capability. */ > > - if (cpuid_ecx(7) & F(LA57)) > > - kvm_cpu_cap_set(X86_FEATURE_LA57); > > > > /* > > * PKU not yet implemented for shadow paging and requires OSPKE > > Putting a function call into a macro which evaluates into a bitmask is somewhat misleading, > but let it be... And weird. Rather than abuse kvm_cpu_cap_set(), what about adding another variable scoped to kvm_cpu_cap_init()? diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 0e64a6332052..b8bc8713a0ec 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -87,12 +87,10 @@ u32 xstate_required_size(u64 xstate_bv, bool compacted) /* * Raw Feature - For features that KVM supports based purely on raw host CPUID, * i.e. that KVM virtualizes even if the host kernel doesn't use the feature. - * Simply force set the feature in KVM's capabilities, raw CPUID support will - * be factored in by __kvm_cpu_cap_mask(). */ #define RAW_F(name) \ ({ \ - kvm_cpu_cap_set(X86_FEATURE_##name); \ + kvm_cpu_cap_passthrough |= F(name); \ F(name); \ }) @@ -737,6 +735,7 @@ do { \ do { \ const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); \ const u32 __maybe_unused kvm_cpu_cap_init_in_progress = leaf; \ + u32 kvm_cpu_cap_passthrough = 0; \ u32 kvm_cpu_cap_emulated = 0; \ u32 kvm_cpu_cap_synthesized = 0; \ \ @@ -745,6 +744,7 @@ do { \ else \ kvm_cpu_caps[leaf] = (mask); \ \ + kvm_cpu_caps[leaf] |= kvm_cpu_cap_passthrough; \ kvm_cpu_caps[leaf] &= (raw_cpuid_get(cpuid) | \ kvm_cpu_cap_synthesized); \ kvm_cpu_caps[leaf] |= kvm_cpu_cap_emulated; \