From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: 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,
Junaid Shahid <junaids@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
Lai Jiangshan <laijs@linux.alibaba.com>
Subject: Re: [PATCH 15/15] KVM: nVMX: Drop redundant checks on vmcs12 in EPTP switching emulation
Date: Thu, 10 Jun 2021 18:09:56 +0200 [thread overview]
Message-ID: <ec192ad8-9ad7-d40a-02e6-07a0dec12607@redhat.com> (raw)
In-Reply-To: <20210609234235.1244004-16-seanjc@google.com>
On 10/06/21 01:42, Sean Christopherson wrote:
> Drop the explicit checks on EPTP switching and EPT itself being enabled.
> The EPTP switching check is handled in the generic VMFUNC function check,
> the underlying VMFUNC enablement check is done by hardware and redone
> by generic VMFUNC emulation, and the vmcs12 EPT check is handled by KVM
> at VM-Enter in the form of a consistency check.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/vmx/nested.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 0075d3f0f8fa..479ec9378609 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5448,10 +5448,6 @@ static int nested_vmx_eptp_switching(struct kvm_vcpu *vcpu,
> u32 index = kvm_rcx_read(vcpu);
> u64 new_eptp;
>
> - if (!nested_cpu_has_eptp_switching(vmcs12) ||
> - !nested_cpu_has_ept(vmcs12))
> - return 1;
> -
Perhaps the EPT enabled check is worth keeping with a WARN_ON_ONCE?
Paolo
> if (index >= VMFUNC_EPTP_ENTRIES)
> return 1;
>
>
next prev parent reply other threads:[~2021-06-10 16:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 23:42 [PATCH 00/15] KVM: x86/mmu: TLB fixes and related cleanups Sean Christopherson
2021-06-09 23:42 ` [PATCH 01/15] KVM: nVMX: Sync all PGDs on nested transition with shadow paging Sean Christopherson
2021-06-09 23:42 ` [PATCH 02/15] KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap Sean Christopherson
2021-06-09 23:42 ` [PATCH 03/15] KVM: nVMX: Don't clobber nested MMU's A/D status on EPTP switch Sean Christopherson
2021-06-09 23:42 ` [PATCH 04/15] KVM: x86: Invalidate all PGDs for the current PCID on MOV CR3 w/ flush Sean Christopherson
2021-06-09 23:42 ` [PATCH 05/15] KVM: x86: Uncondtionally skip MMU sync/TLB flush in MOV CR3's PGD switch Sean Christopherson
2021-06-09 23:42 ` [PATCH 06/15] KVM: nSVM: Move TLB flushing logic (or lack thereof) to dedicated helper Sean Christopherson
2021-06-09 23:42 ` [PATCH 07/15] KVM: x86: Drop skip MMU sync and TLB flush params from "new PGD" helpers Sean Christopherson
2021-06-09 23:42 ` [PATCH 08/15] KVM: nVMX: Consolidate VM-Enter/VM-Exit TLB flush and MMU sync logic Sean Christopherson
2021-06-09 23:42 ` [PATCH 09/15] KVM: nVMX: Free only guest_mode (L2) roots on INVVPID w/o EPT Sean Christopherson
2021-06-09 23:42 ` [PATCH 10/15] KVM: x86: Use KVM_REQ_TLB_FLUSH_GUEST to handle INVPCID(ALL) emulation Sean Christopherson
2021-06-09 23:42 ` [PATCH 11/15] KVM: nVMX: Use fast PGD switch when emulating VMFUNC[EPTP_SWITCH] Sean Christopherson
2021-06-09 23:42 ` [PATCH 12/15] KVM: x86: Defer MMU sync on PCID invalidation Sean Christopherson
2021-06-09 23:42 ` [PATCH 13/15] KVM: x86: Drop pointless @reset_roots from kvm_init_mmu() Sean Christopherson
2021-06-09 23:42 ` [PATCH 14/15] KVM: nVMX: WARN if subtly-impossible VMFUNC conditions occur Sean Christopherson
2021-06-09 23:42 ` [PATCH 15/15] KVM: nVMX: Drop redundant checks on vmcs12 in EPTP switching emulation Sean Christopherson
2021-06-10 16:09 ` Paolo Bonzini [this message]
2021-06-10 16:10 ` [PATCH 00/15] KVM: x86/mmu: TLB fixes and related cleanups 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=ec192ad8-9ad7-d40a-02e6-07a0dec12607@redhat.com \
--to=pbonzini@redhat.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=junaids@google.com \
--cc=kvm@vger.kernel.org \
--cc=laijs@linux.alibaba.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mlevitsk@redhat.com \
--cc=seanjc@google.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
all inboxes | Powered by JetHome®