From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Xin Li <xin@zytor.com>, Dapeng Mi <dapeng1.mi@linux.intel.com>,
Sandipan Das <sandipan.das@amd.com>
Subject: Re: [PATCH 05/18] KVM: x86: Unconditionally handle MSR_IA32_TSC_DEADLINE in fastpath exits
Date: Wed, 6 Aug 2025 10:42:27 -0700 [thread overview]
Message-ID: <aJOUA36kOYklPzXt@google.com> (raw)
In-Reply-To: <20250805190526.1453366-6-seanjc@google.com>
On Tue, Aug 05, 2025, Sean Christopherson wrote:
> Stating the obvious, this allows handling MSR_IA32_TSC_DEADLINE writes in
> the fastpath on AMD CPUs.
Got around to measuring this via the KUT vmexit "tscdeadline_immed" test. Without
the mediated PMU, the gains are very modest: ~2550 => ~2400 cycles. But with the
mediated PMU and its heavy context switch, the gains are ~6100 => ~2400 cycles.
next prev parent reply other threads:[~2025-08-06 17:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-05 19:05 [PATCH 00/18] KVM: x86: Fastpath cleanups and PMU prep work Sean Christopherson
2025-08-05 19:05 ` [PATCH 01/18] KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Sean Christopherson
2025-08-05 19:05 ` [PATCH 02/18] KVM: x86: Add kvm_icr_to_lapic_irq() helper to allow for fastpath IPIs Sean Christopherson
2025-08-05 19:05 ` [PATCH 03/18] KVM: x86: Only allow "fast" IPIs in fastpath WRMSR(X2APIC_ICR) handler Sean Christopherson
2025-08-05 19:05 ` [PATCH 04/18] KVM: x86: Drop semi-arbitrary restrictions on IPI type in fastpath Sean Christopherson
2025-08-05 19:05 ` [PATCH 05/18] KVM: x86: Unconditionally handle MSR_IA32_TSC_DEADLINE in fastpath exits Sean Christopherson
2025-08-06 17:42 ` Sean Christopherson [this message]
2025-08-05 19:05 ` [PATCH 06/18] KVM: x86: Acquire SRCU in WRMSR fastpath iff instruction needs to be skipped Sean Christopherson
2025-08-05 19:05 ` [PATCH 07/18] KVM: x86: Unconditionally grab data from EDX:EAX in WRMSR fastpath Sean Christopherson
2025-08-05 19:05 ` [PATCH 08/18] KVM: x86: Fold WRMSR fastpath helpers into the main handler Sean Christopherson
2025-08-05 19:05 ` [PATCH 09/18] KVM: x86/pmu: Move kvm_init_pmu_capability() to pmu.c Sean Christopherson
2025-08-06 7:23 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 10/18] KVM: x86/pmu: Add wrappers for counting emulated instructions/branches Sean Christopherson
2025-08-06 7:25 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 11/18] KVM: x86/pmu: Calculate set of to-be-emulated PMCs at time of WRMSRs Sean Christopherson
2025-08-06 7:28 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 12/18] KVM: x86/pmu: Rename pmc_speculative_in_use() to pmc_is_locally_enabled() Sean Christopherson
2025-08-06 7:28 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 13/18] KVM: x86/pmu: Open code pmc_event_is_allowed() in its callers Sean Christopherson
2025-08-06 7:30 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 14/18] KVM: x86/pmu: Drop redundant check on PMC being globally enabled for emulation Sean Christopherson
2025-08-06 7:32 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 15/18] KVM: x86/pmu: Drop redundant check on PMC being locally " Sean Christopherson
2025-08-06 7:33 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 16/18] KVM: x86/pmu: Rename check_pmu_event_filter() to pmc_is_event_allowed() Sean Christopherson
2025-08-06 7:35 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 17/18] KVM: x86: Push acquisition of SRCU in fastpath into kvm_pmu_trigger_event() Sean Christopherson
2025-08-06 8:08 ` Mi, Dapeng
2025-08-06 17:33 ` Sean Christopherson
2025-08-07 2:24 ` Mi, Dapeng
2025-08-07 13:31 ` Sean Christopherson
2025-08-08 0:42 ` Mi, Dapeng
2025-08-05 19:05 ` [PATCH 18/18] KVM: x86: Add a fastpath handler for INVD Sean Christopherson
2025-08-06 8:11 ` [PATCH 00/18] KVM: x86: Fastpath cleanups and PMU prep work Mi, Dapeng
2025-08-07 6:23 ` Sandipan Das
2025-08-19 23:11 ` Sean Christopherson
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