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 1/5] KVM: nVMX: Invoke ept_save_pdptrs() if and only if PAE paging is enabled
Date: Wed, 15 Apr 2020 13:34:50 -0700 [thread overview]
Message-ID: <20200415203454.8296-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200415203454.8296-1-sean.j.christopherson@intel.com>
Invoke ept_save_pdptrs() when restoring L1's host state on a "late"
VM-Fail if and only if PAE paging is enabled. This saves a CALL in the
common case where L1 is a 64-bit host, and avoids incorrectly marking
the PDPTRs as dirty.
WARN if ept_save_pdptrs() is called with PAE disabled now that the
nested usage pre-checks is_pae_paging(). Barring a bug in KVM's MMU,
attempting to read the PDPTRs with PAE disabled is now impossible.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/nested.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 13 +++++++------
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index aca57d8da400..f9ae42209d78 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4250,7 +4250,7 @@ static void nested_vmx_restore_host_state(struct kvm_vcpu *vcpu)
* VMFail, like everything else we just need to ensure our
* software model is up-to-date.
*/
- if (enable_ept)
+ if (enable_ept && is_pae_paging(vcpu))
ept_save_pdptrs(vcpu);
kvm_mmu_reset_context(vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index aa1b8cf7c915..7da83325ace3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2937,12 +2937,13 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
- if (is_pae_paging(vcpu)) {
- mmu->pdptrs[0] = vmcs_read64(GUEST_PDPTR0);
- mmu->pdptrs[1] = vmcs_read64(GUEST_PDPTR1);
- mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
- mmu->pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
- }
+ if (WARN_ON_ONCE(!is_pae_paging(vcpu)))
+ return;
+
+ mmu->pdptrs[0] = vmcs_read64(GUEST_PDPTR0);
+ mmu->pdptrs[1] = vmcs_read64(GUEST_PDPTR1);
+ mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
+ mmu->pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
}
--
2.26.0
next prev parent reply other threads:[~2020-04-15 20:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 20:34 [PATCH 0/5] KVM: VMX: Add caching of EXIT_QUAL and INTR_INFO Sean Christopherson
2020-04-15 20:34 ` Sean Christopherson [this message]
2020-04-15 20:34 ` [PATCH 2/5] KVM: nVMX: Reset register cache (available and dirty masks) on VMCS switch Sean Christopherson
2020-04-15 20:34 ` [PATCH 3/5] KVM: nVMX: Drop manual clearing of segment cache on nested " Sean Christopherson
2020-04-15 20:34 ` [PATCH 4/5] KVM: VMX: Cache vmcs.EXIT_QUALIFICATION using arch avail_reg flags Sean Christopherson
2020-04-15 20:34 ` [PATCH 5/5] KVM: VMX: Cache vmcs.EXIT_INTR_INFO " Sean Christopherson
2020-04-16 13:42 ` [PATCH 0/5] KVM: VMX: Add caching of EXIT_QUAL and INTR_INFO Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200415203454.8296-2-sean.j.christopherson@intel.com \
--to=sean.j.christopherson@intel.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).