From: Xin Li <xin@zytor.com>
To: Chao Gao <chao.gao@intel.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
pbonzini@redhat.com, seanjc@google.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com
Subject: Re: [PATCH v1 2/4] KVM: x86: Introduce MSR read/write emulation helpers
Date: Thu, 31 Jul 2025 10:19:48 -0700 [thread overview]
Message-ID: <02257a58-393b-4687-803a-e9b3d6bcb786@zytor.com> (raw)
In-Reply-To: <7af6dcf5-fbcd-4173-a588-38cf6c536282@zytor.com>
On 7/31/2025 9:40 AM, Xin Li wrote:
>>> +
>>> handled = !handle_fastpath_set_x2apic_icr_irqoff(vcpu, data);
>>> break;
>>> case MSR_IA32_TSC_DEADLINE:
>>> - data = kvm_read_edx_eax(vcpu);
>>> + if (reg == VCPU_EXREG_EDX_EAX)
>>> + data = kvm_read_edx_eax(vcpu);
>>> + else
>>> + data = kvm_register_read(vcpu, reg);
>>> +
>>
>> Hoist this chunk out of the switch clause to avoid duplication.
>
> I thought about it, but didn't do so because the original code doesn't
> read the MSR data from registers when a MSR is not being handled in the
> fast path, which saves some cycles in most cases.
I think I can make it an inline function.
next prev parent reply other threads:[~2025-07-31 17:20 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-30 17:46 [PATCH v1 0/4] KVM: VMX: Handle the immediate form of MSR instructions Xin Li (Intel)
2025-07-30 17:46 ` [PATCH v1 1/4] x86/cpufeatures: Add a CPU feature bit for MSR immediate form instructions Xin Li (Intel)
2025-07-30 17:46 ` [PATCH v1 2/4] KVM: x86: Introduce MSR read/write emulation helpers Xin Li (Intel)
2025-07-31 10:34 ` Chao Gao
2025-07-31 16:40 ` Xin Li
2025-07-31 17:19 ` Xin Li [this message]
2025-08-01 0:47 ` Sean Christopherson
2025-08-01 1:35 ` Xin Li
2025-08-01 14:37 ` Sean Christopherson
2025-08-01 16:27 ` Xin Li
2025-07-30 17:46 ` [PATCH v1 3/4] KVM: VMX: Handle the immediate form of MSR instructions Xin Li (Intel)
2025-07-31 11:04 ` Chao Gao
2025-07-31 16:53 ` Xin Li
2025-07-31 22:10 ` Xin Li
2025-07-30 17:46 ` [PATCH v1 4/4] KVM: x86: Advertise support for " Xin Li (Intel)
2025-08-01 14:39 ` Sean Christopherson
2025-08-01 16:11 ` Xin Li
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