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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Jim Mattson" <jmattson@google.com>,
	"Liran Alon" <liran.alon@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v1 RESEND 9/9] x86/kvm/mmu: check if MMU reconfiguration is needed in init_kvm_nested_mmu()
Date: Tue, 18 Sep 2018 18:09:06 +0200	[thread overview]
Message-ID: <20180918160906.9241-10-vkuznets@redhat.com> (raw)
In-Reply-To: <20180918160906.9241-1-vkuznets@redhat.com>

We don't use root page role for nested_mmu, however, optimizing out
re-initialization in case nothing changed is still valuable as this
is done for every nested vmentry.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/mmu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ecd5e9fd3f8c..c7b077179485 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4907,8 +4907,14 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
 
 static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
 {
+	union kvm_mmu_role new_role = kvm_calc_mmu_role_common(vcpu, true);
 	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
 
+	new_role.base_role.word &= mmu_base_role_mask.word;
+	if (new_role.as_u64 == g_context->mmu_role.as_u64)
+		return;
+
+	g_context->mmu_role.as_u64 = new_role.as_u64;
 	g_context->get_cr3           = get_cr3;
 	g_context->get_pdptr         = kvm_pdptr_read;
 	g_context->inject_page_fault = kvm_inject_page_fault;
-- 
2.14.4


      parent reply	other threads:[~2018-09-18 16:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-18 16:08 [PATCH v1 RESEND 0/9] x86/kvm/nVMX: optimize MMU switch between L1 and L2 Vitaly Kuznetsov
2018-09-18 16:08 ` [PATCH v1 RESEND 1/9] x86/kvm/mmu: make vcpu->mmu a pointer to the current MMU Vitaly Kuznetsov
2018-09-18 16:08 ` [PATCH v1 RESEND 2/9] x86/kvm/mmu.c: set get_pdptr hook in kvm_init_shadow_ept_mmu() Vitaly Kuznetsov
2018-09-18 16:09 ` [PATCH v1 RESEND 3/9] x86/kvm/mmu.c: add kvm_mmu parameter to kvm_mmu_free_roots() Vitaly Kuznetsov
2018-09-18 16:09 ` [PATCH v1 RESEND 4/9] x86/kvm/mmu: introduce guest_mmu Vitaly Kuznetsov
2018-09-19 15:08   ` Sean Christopherson
2018-09-18 16:09 ` [PATCH v1 RESEND 5/9] x86/kvm/mmu: get rid of redundant kvm_mmu_setup() Vitaly Kuznetsov
2018-09-18 16:09 ` [PATCH v1 RESEND 6/9] x86/kvm/mmu: make space for source data caching in struct kvm_mmu Vitaly Kuznetsov
2018-09-19 15:30   ` Sean Christopherson
2018-09-18 16:09 ` [PATCH v1 RESEND 7/9] x86/kvm/nVMX: introduce scache for kvm_init_shadow_ept_mmu Vitaly Kuznetsov
2018-09-18 16:09 ` [PATCH v1 RESEND 8/9] x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed Vitaly Kuznetsov
2018-09-18 16:09 ` Vitaly Kuznetsov [this message]

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