From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 2/3] KVM: X86: Provides userspace with a capability to not intercept HLT
Date: Thu, 8 Mar 2018 21:40:29 +0100 [thread overview]
Message-ID: <20180308204029.GK12290@flask> (raw)
In-Reply-To: <1519897782-8124-2-git-send-email-wanpengli@tencent.com>
2018-03-01 17:49+0800, Wanpeng Li:
> From: Wanpeng Li <wanpengli@tencent.com>
>
> If host CPUs are dedicated to a VM, we can avoid VM exits on HLT.
> This patch adds the per-VM non-HLT-exiting capability.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index dff3a5d..fcf8339 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1394,6 +1394,9 @@ static void init_vmcb(struct vcpu_svm *svm)
> set_intercept(svm, INTERCEPT_MWAIT);
> }
>
> + if (!kvm_hlt_in_guest(svm->vcpu.kvm))
> + set_intercept(svm, INTERCEPT_HLT);
We unconditionally set INTERCEPT_HLT just above, so that line has to be
removed.
> +
> control->iopm_base_pa = __sme_set(iopm_base);
> control->msrpm_base_pa = __sme_set(__pa(svm->msrpm));
> control->int_ctl = V_INTR_MASKING_MASK;
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> @@ -2525,6 +2525,19 @@ static int nested_vmx_check_exception(struct kvm_vcpu *vcpu, unsigned long *exit
> return 0;
> }
>
> +static void vmx_clear_hlt(struct kvm_vcpu *vcpu)
> +{
> + /*
> + * Ensure that we clear the HLT state in the VMCS. We don't need to
> + * explicitly skip the instruction because if the HLT state is set,
> + * then the instruction is already executing and RIP has already been
> + * advanced.
> + */
> + if (kvm_hlt_in_guest(vcpu->kvm) &&
> + vmcs_read32(GUEST_ACTIVITY_STATE) == GUEST_ACTIVITY_HLT)
> + vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE);
> +}
The clearing seems to be still missing around SMM -- I think you need to
call vmx_clear_hlt() from pre_enter_smm().
Thanks.
next prev parent reply other threads:[~2018-03-08 20:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 9:49 [PATCH 1/3] KVM: X86: Provides userspace with a capability to not intercept MWAIT Wanpeng Li
2018-03-01 9:49 ` [PATCH 2/3] KVM: X86: Provides userspace with a capability to not intercept HLT Wanpeng Li
2018-03-08 20:40 ` Radim Krčmář [this message]
2018-03-09 0:51 ` Wanpeng Li
2018-03-01 9:49 ` [PATCH 3/3] KVM: X86: Provides userspace with a capability to not intercept PAUSE Wanpeng Li
2018-03-08 20:52 ` Radim Krčmář
2018-03-08 20:31 ` [PATCH 1/3] KVM: X86: Provides userspace with a capability to not intercept MWAIT Radim Krčmář
2018-03-08 20:55 ` Radim Krčmář
2018-03-09 2:34 ` Wanpeng Li
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=20180308204029.GK12290@flask \
--to=rkrcmar@redhat.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.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).