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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=O0T11VSCmFTbIxvLi3sB7dCbnWaTDjaBGygjXrtPM+v8lTnw9Tful2/e6/ZNNvdCg Ru3XxSgfQ8RgZP4tlBcIQ49RJ2Pgyo4oC/UJyZAXxtJGYINJ1/IBSW7lmVxU2bQLfN u/dFSJNtZSiyDk44R2dihFQeQf9mvnXB/kVprJ3PMIe6RYjH3WuyIRB7SOq6HDujqJ TaVgvyHoiUueE3GrkGXHzeUy1HebH4sN8yxWuWnMzgmZM+uAo3mh2yXLgUMWQjLdRg 5qhY0gxYta4QSYHOitsCREWQoyxY4g+jA+6erntu715vASIw2qqj3Oa2PZxUoMfkeR KbBjvAyPG6YxA== Message-ID: <10eb00d1-36d8-449e-90a6-a315544c53e1@zytor.com> Date: Wed, 6 Aug 2025 08:59:23 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/4] KVM: VMX: Handle the immediate form of MSR instructions To: Sean Christopherson Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, chao.gao@intel.com References: <20250802001520.3142577-1-xin@zytor.com> <20250802001520.3142577-3-xin@zytor.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/5/2025 1:03 PM, Sean Christopherson wrote: > On Fri, Aug 01, 2025, Xin Li (Intel) wrote: >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index f19a76d3ca0e..c5d0082cf0a5 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -978,6 +978,7 @@ struct kvm_vcpu_arch { >> unsigned long guest_debug_dr7; >> u64 msr_platform_info; >> u64 msr_misc_features_enables; >> + u32 cui_rdmsr_imm_reg; > > This should be an "int", mostly because that's how KVM tracks it throughout the > various accessors, but also because it'd let us use "-1" for an "invalid" value, > e.g. if we ever want to add sanity checks to the completion callback (I don't > think that's worth doing). Sigh, using u32 was a dumb move on my part. >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index a1c49bc681c4..fe12aae7089c 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -1968,6 +1968,13 @@ static void complete_userspace_rdmsr(struct kvm_vcpu *vcpu) >> } >> } >> >> +static void complete_userspace_rdmsr_imm(struct kvm_vcpu *vcpu) > > No need for this helper, the few lines can be open coded in complete_fast_rdmsr_imm(). Yes, the change in v3 is simpler. > >> +{ >> + if (!vcpu->run->msr.error) >> + kvm_register_write(vcpu, vcpu->arch.cui_rdmsr_imm_reg, >> + vcpu->run->msr.data); >> +} >> + >