Re: [PATCH 11/21] KVM: x86/mmu: Zero allocate shadow pages (outside of mmu_lock)
From: Ben Gardon <hidden>
Date: 2020-06-10 18:49:19
Also in:
kvm, kvmarm, linux-mips, lkml
On Fri, Jun 5, 2020 at 2:39 PM Sean Christopherson [off-list ref] wrote:
Set __GFP_ZERO for the shadow page memory cache and drop the explicit clear_page() from kvm_mmu_get_page(). This moves the cost of zeroing a page to the allocation time of the physical page, i.e. when topping up the memory caches, and thus avoids having to zero out an entire page while holding mmu_lock. Cc: Peter Feiner <redacted> Cc: Peter Shier <redacted> Cc: Junaid Shahid <redacted> Cc: Jim Mattson <redacted> Suggested-by: Ben Gardon <redacted> Signed-off-by: Sean Christopherson <redacted>
Reviewed-by: Ben Gardon <redacted>
quoted hunk ↗ jump to hunk
--- arch/x86/kvm/mmu/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6b0ec9060786..a8f8eebf67df 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c@@ -2545,7 +2545,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, if (level > PG_LEVEL_4K && need_sync) flush |= kvm_sync_pages(vcpu, gfn, &invalid_list); } - clear_page(sp->spt); trace_kvm_mmu_get_page(sp, true); kvm_mmu_flush_or_zap(vcpu, &invalid_list, false, flush);@@ -5687,6 +5686,8 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; --2.26.0
_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel