From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.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,
Ben Gardon <bgardon@google.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH 11/15] KVM: nVMX: Defer the MMU reload to the normal path on an EPTP switch
Date: Tue, 2 Mar 2021 10:45:36 -0800 [thread overview]
Message-ID: <20210302184540.2829328-12-seanjc@google.com> (raw)
In-Reply-To: <20210302184540.2829328-1-seanjc@google.com>
Defer reloading the MMU after a EPTP successful EPTP switch. The VMFUNC
instruction itself is executed in the previous EPTP context, any side
effects, e.g. updating RIP, should occur in the old context. Practically
speaking, this bug is benign as VMX doesn't touch the MMU when skipping
an emulated instruction, nor does queuing a single-step #DB. No other
post-switch side effects exist.
Fixes: 41ab93727467 ("KVM: nVMX: Emulate EPTP switching for the L1 hypervisor")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/nested.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index fdd80dd8e781..81f609886c8b 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5473,16 +5473,11 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu,
if (!nested_vmx_check_eptp(vcpu, new_eptp))
return 1;
- kvm_mmu_unload(vcpu);
mmu->ept_ad = accessed_dirty;
mmu->mmu_role.base.ad_disabled = !accessed_dirty;
vmcs12->ept_pointer = new_eptp;
- /*
- * TODO: Check what's the correct approach in case
- * mmu reload fails. Currently, we just let the next
- * reload potentially fail
- */
- kvm_mmu_reload(vcpu);
+
+ kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
}
return 0;
--
2.30.1.766.gb4fecdf3b7-goog
next prev parent reply other threads:[~2021-03-02 22:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 18:45 [PATCH 00/15] KVM: x86/mmu: Lots of bug fixes Sean Christopherson
2021-03-02 18:45 ` [PATCH 01/15] KVM: nSVM: Set the shadow root level to the TDP level for nested NPT Sean Christopherson
2021-03-02 18:45 ` [PATCH 02/15] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit Sean Christopherson
2021-03-03 17:28 ` Ben Gardon
2021-03-02 18:45 ` [PATCH 03/15] KVM: x86/mmu: Ensure MMU pages are available when allocating roots Sean Christopherson
2021-03-03 0:21 ` Ben Gardon
2021-03-03 16:46 ` Sean Christopherson
2021-03-02 18:45 ` [PATCH 04/15] KVM: x86/mmu: Allocate the lm_root before allocating PAE roots Sean Christopherson
2021-03-02 18:45 ` [PATCH 05/15] KVM: x86/mmu: Check PDPTRs " Sean Christopherson
2021-03-02 18:45 ` [PATCH 06/15] KVM: x86/mmu: Fix and unconditionally enable WARNs to detect PAE leaks Sean Christopherson
2021-03-02 18:45 ` [PATCH 07/15] KVM: x86/mmu: Use '0' as the one and only value for an invalid PAE root Sean Christopherson
2021-03-02 18:45 ` [PATCH 08/15] KVM: x86/mmu: Set the C-bit in the PDPTRs and LM pseudo-PDPTRs Sean Christopherson
2021-03-02 18:45 ` [PATCH 09/15] KVM: x86/mmu: Mark the PAE roots as decrypted for shadow paging Sean Christopherson
2021-03-02 18:45 ` [PATCH 10/15] KVM: SVM: Don't strip the C-bit from CR2 on #PF interception Sean Christopherson
2021-03-02 18:45 ` Sean Christopherson [this message]
2021-03-02 18:45 ` [PATCH 12/15] KVM: x86: Defer the MMU unload to the normal path on an global INVPCID Sean Christopherson
2021-03-02 18:45 ` [PATCH 13/15] KVM: x86/mmu: Unexport MMU load/unload functions Sean Christopherson
2021-03-02 18:45 ` [PATCH 14/15] KVM: x86/mmu: Sync roots after MMU load iff load as successful Sean Christopherson
2021-03-02 18:45 ` [PATCH 15/15] KVM: x86/mmu: WARN on NULL pae_root and bad shadow root level Sean Christopherson
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=20210302184540.2829328-12-seanjc@google.com \
--to=seanjc@google.com \
--cc=bgardon@google.com \
--cc=brijesh.singh@amd.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=thomas.lendacky@amd.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).