From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.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
Subject: [PATCH 1/7] KVM: nVMX: Use correct root level for nested EPT shadow page tables
Date: Thu, 6 Feb 2020 14:08:30 -0800 [thread overview]
Message-ID: <20200206220836.22743-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200206220836.22743-1-sean.j.christopherson@intel.com>
Hardcode the EPT page-walk level for L2 to be 4 levels, as KVM's MMU
currently also hardcodes the page walk level for nested EPT to be 4
levels. The L2 guest is all but guaranteed to soft hang on its first
instruction when L1 is using EPT, as KVM will construct 4-level page
tables and then tell hardware to use 5-level page tables.
Fixes: 855feb673640 ("KVM: MMU: Add 5 level EPT & Shadow page table support.")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 802ba97ac7f2..46161f4e4b42 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2970,6 +2970,9 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
static int get_ept_level(struct kvm_vcpu *vcpu)
{
+ /* Nested EPT currently only supports 4-level walks. */
+ if (is_guest_mode(vcpu) && nested_cpu_has_ept(get_vmcs12(vcpu)))
+ return 4;
if (cpu_has_vmx_ept_5levels() && (cpuid_maxphyaddr(vcpu) > 48))
return 5;
return 4;
--
2.24.1
next prev parent reply other threads:[~2020-02-06 22:09 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 22:08 [PATCH 0/7] KVM: x86/mmu: nVMX: 5-level paging fixes and enabling Sean Christopherson
2020-02-06 22:08 ` Sean Christopherson [this message]
2020-02-06 22:08 ` [PATCH 2/7] KVM: x86/mmu: Fix struct guest_walker arrays for 5-level paging Sean Christopherson
2020-02-06 23:07 ` Sean Christopherson
2020-02-06 22:08 ` [PATCH 3/7] KVM: nVMX: Allow L1 to use 5-level page walks for nested EPT Sean Christopherson
2020-02-06 22:08 ` [PATCH 4/7] KVM: nVMX: Rename nested_ept_get_cr3() to nested_ept_get_eptp() Sean Christopherson
2020-02-06 22:08 ` [PATCH 5/7] KVM: nVMX: Rename EPTP validity helper and associated variables Sean Christopherson
2020-02-06 22:08 ` [PATCH 6/7] KVM: x86/mmu: Rename kvm_mmu->get_cr3() to ->get_guest_cr3_or_eptp() Sean Christopherson
2020-02-06 22:08 ` [PATCH 7/7] KVM: nVMX: Drop unnecessary check on ept caps for execute-only Sean Christopherson
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