[12/15] KVM: x86: Defer MMU sync on PCID invalidation

Message ID	20210609234235.1244004-13-seanjc@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> Reply-To: Sean Christopherson <seanjc@google.com> Date: Wed, 9 Jun 2021 16:42:32 -0700 In-Reply-To: <20210609234235.1244004-1-seanjc@google.com> Message-Id: <20210609234235.1244004-13-seanjc@google.com> Mime-Version: 1.0 References: <20210609234235.1244004-1-seanjc@google.com> Subject: [PATCH 12/15] KVM: x86: Defer MMU sync on PCID invalidation From: Sean Christopherson <seanjc@google.com> To: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com>, Vitaly Kuznetsov <vkuznets@redhat.com>, Wanpeng Li <wanpengli@tencent.com>, Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Junaid Shahid <junaids@google.com>, Maxim Levitsky <mlevitsk@redhat.com>, Lai Jiangshan <laijs@linux.alibaba.com> Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	KVM: x86/mmu: TLB fixes and related cleanups \| expand [00/15] KVM: x86/mmu: TLB fixes and related cleanups [01/15] KVM: nVMX: Sync all PGDs on nested transition with shadow paging [02/15] KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap [03/15] KVM: nVMX: Don't clobber nested MMU's A/D status on EPTP switch [04/15] KVM: x86: Invalidate all PGDs for the current PCID on MOV CR3 w/ flush [05/15] KVM: x86: Uncondtionally skip MMU sync/TLB flush in MOV CR3's PGD switch [06/15] KVM: nSVM: Move TLB flushing logic (or lack thereof) to dedicated helper [07/15] KVM: x86: Drop skip MMU sync and TLB flush params from "new PGD" helpers [08/15] KVM: nVMX: Consolidate VM-Enter/VM-Exit TLB flush and MMU sync logic [09/15] KVM: nVMX: Free only guest_mode (L2) roots on INVVPID w/o EPT [10/15] KVM: x86: Use KVM_REQ_TLB_FLUSH_GUEST to handle INVPCID(ALL) emulation [11/15] KVM: nVMX: Use fast PGD switch when emulating VMFUNC[EPTP_SWITCH] [12/15] KVM: x86: Defer MMU sync on PCID invalidation [13/15] KVM: x86: Drop pointless @reset_roots from kvm_init_mmu() [14/15] KVM: nVMX: WARN if subtly-impossible VMFUNC conditions occur [15/15] KVM: nVMX: Drop redundant checks on vmcs12 in EPTP switching emulation

Message ID

20210609234235.1244004-13-seanjc@google.com (mailing list archive)

State

New, archived

Headers

Reply-To: Sean Christopherson <seanjc@google.com>
Date: Wed,  9 Jun 2021 16:42:32 -0700
In-Reply-To: <20210609234235.1244004-1-seanjc@google.com>
Message-Id: <20210609234235.1244004-13-seanjc@google.com>
Mime-Version: 1.0
References: <20210609234235.1244004-1-seanjc@google.com>
Subject: [PATCH 12/15] KVM: x86: Defer MMU sync on PCID invalidation
From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Junaid Shahid <junaids@google.com>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        Lai Jiangshan <laijs@linux.alibaba.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Series

KVM: x86/mmu: TLB fixes and related cleanups | expand

Commit Message

Sean Christopherson June 9, 2021, 11:42 p.m. UTC

Defer the MMU sync on PCID invalidation so that multiple sync requests in
a single VM-Exit are batched.  This is a very minor optimization as
checking for unsync'd children is quite cheap.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9620d8936dc4..d3a2a3375541 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1096,7 +1096,7 @@  static void kvm_invalidate_pcid(struct kvm_vcpu *vcpu, unsigned long pcid)
 	 * happen anyway before switching to any other CR3.
 	 */
 	if (kvm_get_active_pcid(vcpu) == pcid) {
-		kvm_mmu_sync_roots(vcpu);
+		kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
 		kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
 	}

[12/15] KVM: x86: Defer MMU sync on PCID invalidation

Commit Message

Patch