From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: [RFC PATCH 1/6] KVM: X86: Check root_level only in fast_pgd_switch()
Date: Fri, 10 Dec 2021 17:25:03 +0800 [thread overview]
Message-ID: <20211210092508.7185-2-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20211210092508.7185-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <laijs@linux.alibaba.com>
If root_level >= 4, shadow_root_level must be >= 4 too.
Checking only root_level can reduce a check.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/kvm/mmu/mmu.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 11b06d536cc9..846a2e426e0b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4136,8 +4136,7 @@ static bool fast_pgd_switch(struct kvm_vcpu *vcpu, gpa_t new_pgd,
* having to deal with PDPTEs. We may add support for 32-bit hosts/VMs
* later if necessary.
*/
- if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&
- mmu->root_level >= PT64_ROOT_4LEVEL)
+ if (mmu->root_level >= PT64_ROOT_4LEVEL)
return cached_root_available(vcpu, new_pgd, new_role);
return false;
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2021-12-10 9:25 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 9:25 [RFC PATCH 0/6] KVM: X86: Add and use shadow page with level promoted or acting as pae_root Lai Jiangshan
2021-12-10 9:25 ` Lai Jiangshan [this message]
2022-01-04 20:24 ` [RFC PATCH 1/6] KVM: X86: Check root_level only in fast_pgd_switch() Sean Christopherson
2021-12-10 9:25 ` [RFC PATCH 2/6] KVM: X86: Walk shadow page starting with shadow_root_level Lai Jiangshan
2022-01-04 20:34 ` Sean Christopherson
2022-01-04 20:37 ` Paolo Bonzini
2022-01-04 20:43 ` Maxim Levitsky
2021-12-10 9:25 ` [RFC PATCH 3/6] KVM: X86: Add arguement gfn and role to kvm_mmu_alloc_page() Lai Jiangshan
2022-01-04 20:53 ` Sean Christopherson
2021-12-10 9:25 ` [RFC PATCH 4/6] KVM: X86: Introduce role.level_promoted Lai Jiangshan
2022-01-04 22:14 ` Sean Christopherson
2022-02-11 16:06 ` Paolo Bonzini
2021-12-10 9:25 ` [RFC PATCH 5/6] KVM: X86: Alloc pae_root shadow page Lai Jiangshan
2022-01-04 21:54 ` Sean Christopherson
2022-01-05 3:11 ` Lai Jiangshan
2022-01-05 16:45 ` Sean Christopherson
2022-01-06 2:01 ` Lai Jiangshan
2022-01-06 19:41 ` Sean Christopherson
2022-01-07 4:36 ` Lai Jiangshan
2021-12-10 9:25 ` [RFC PATCH 6/6] KVM: X86: Use level_promoted and pae_root shadow page for 32bit guests Lai Jiangshan
2022-01-04 20:55 ` Sean Christopherson
2021-12-10 10:27 ` [RFC PATCH 0/6] KVM: X86: Add and use shadow page with level promoted or acting as pae_root Maxim Levitsky
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