From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: bgardon@google.com
Subject: [PATCH 21/22] kvm: x86/mmu: Don't clear write flooding count for direct roots
Date: Fri, 23 Oct 2020 12:30:23 -0400 [thread overview]
Message-ID: <20201023163024.2765558-22-pbonzini@redhat.com> (raw)
In-Reply-To: <20201023163024.2765558-1-pbonzini@redhat.com>
From: Ben Gardon <bgardon@google.com>
Direct roots don't have a write flooding count because the guest can't
affect that paging structure. Thus there's no need to clear the write
flooding count on a fast CR3 switch for direct roots.
Tested by running kvm-unit-tests and KVM selftests on an Intel Haswell
machine. This series introduced no new failures.
This series can be viewed in Gerrit at:
https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2538
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20201014182700.2888246-20-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6a0941ccac34..7b52fa1f01b0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3892,7 +3892,13 @@ static void __kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd,
*/
vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
- __clear_sp_write_flooding_count(to_shadow_page(vcpu->arch.mmu->root_hpa));
+ /*
+ * If this is a direct root page, it doesn't have a write flooding
+ * count. Otherwise, clear the write flooding count.
+ */
+ if (!new_role.direct)
+ __clear_sp_write_flooding_count(
+ to_shadow_page(vcpu->arch.mmu->root_hpa));
}
void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd, bool skip_tlb_flush,
--
2.26.2
next prev parent reply other threads:[~2020-10-23 16:31 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 16:30 [PATCH 00/22] Introduce the TDP MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 01/22] kvm: mmu: Separate making non-leaf sptes from link_shadow_page Paolo Bonzini
2020-10-23 16:30 ` [PATCH 02/22] kvm: x86/mmu: Separate making SPTEs from set_spte Paolo Bonzini
2020-10-23 16:30 ` [PATCH 03/22] KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp Paolo Bonzini
2020-10-23 16:30 ` [PATCH 04/22] KVM: mmu: extract spte.h and spte.c Paolo Bonzini
2020-10-27 14:46 ` Valdis Klētnieks
2020-10-28 17:36 ` Paolo Bonzini
2020-10-23 16:30 ` [PATCH 05/22] kvm: x86/mmu: Introduce tdp_iter Paolo Bonzini
2020-10-23 16:30 ` [PATCH 06/22] kvm: x86/mmu: Init / Uninit the TDP MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 07/22] kvm: x86/mmu: Allocate and free TDP MMU roots Paolo Bonzini
2020-10-23 16:30 ` [PATCH 08/22] kvm: x86/mmu: Add functions to handle changed TDP SPTEs Paolo Bonzini
2020-10-23 16:30 ` [PATCH 09/22] KVM: Cache as_id in kvm_memory_slot Paolo Bonzini
2020-10-23 16:30 ` [PATCH 10/22] kvm: x86/mmu: Support zapping SPTEs in the TDP MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 11/22] kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg Paolo Bonzini
2020-10-23 16:30 ` [PATCH 12/22] kvm: x86/mmu: Add TDP MMU PF handler Paolo Bonzini
2020-10-23 16:30 ` [PATCH 13/22] kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 14/22] kvm: x86/mmu: Support invalidate range MMU notifier for " Paolo Bonzini
2020-10-23 16:30 ` [PATCH 15/22] kvm: x86/mmu: Add access tracking for tdp_mmu Paolo Bonzini
2020-10-23 16:30 ` [PATCH 16/22] kvm: x86/mmu: Support changed pte notifier in tdp MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 17/22] kvm: x86/mmu: Support dirty logging for the TDP MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 18/22] kvm: x86/mmu: Support disabling dirty logging for the tdp MMU Paolo Bonzini
2020-10-23 16:30 ` [PATCH 19/22] kvm: x86/mmu: Support write protection for nesting in " Paolo Bonzini
2020-10-23 16:30 ` [PATCH 20/22] kvm: x86/mmu: Support MMIO in the TDP MMU Paolo Bonzini
2020-10-23 16:30 ` Paolo Bonzini [this message]
2020-10-23 16:30 ` [PATCH 22/22] kvm: x86/mmu: NX largepage recovery for " Paolo Bonzini
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