From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Bandan Das <bsd@redhat.com>
Cc: Joel Schopp <joel.schopp@amd.com>, Gleb Natapov <gleb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, David Kaplan <David.Kaplan@amd.com>,
Joerg Roedel <joro@8bytes.org>,
Marcelo Tosatti <mtosatti@redhat.com>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH] x86: svm: make wbinvd faster
Date: Mon, 2 Mar 2015 17:03:20 +0100 [thread overview]
Message-ID: <20150302160319.GA25123@potion.brq.redhat.com> (raw)
In-Reply-To: <jpgmw3v2zgx.fsf@redhat.com>
2015-03-02 10:25-0500, Bandan Das:
> Radim Krčmář <rkrcmar@redhat.com> writes:
> > 2015-03-01 21:29-0500, Bandan Das:
> >> Joel Schopp <joel.schopp@amd.com> writes:
> >> > +static int wbinvd_interception(struct vcpu_svm *svm)
> >> > +{
> >> > + kvm_emulate_wbinvd(&svm->vcpu);
> >> > + skip_emulated_instruction(&svm->vcpu);
> >> > + return 1;
> >> > +}
> >> Can't we merge this to kvm_emulate_wbinvd, and just call that function
> >> directly for both vmx and svm ?
> >
> > kvm_emulate_wbinvd() lives in x86.c and skip_emulated_instruction() is
> > from svm.c/vmx.c: so we'd have to create a new x86 op and change the
> > emulator code as well ... it's probably better like this.
>
> There's already one - kvm_x86_ops->skip_emulated_instruction
My bad, its usage is inconsistent and I only looked at two close
interceptions where it was used ... kvm_emulate_cpuid() calls
kvm_x86_ops->skip_emulated_instruction(), while kvm_emulate_halt() and
kvm_emulate_hypercall() need an external skip.
We do "skip" the instruction with kvm_emulate(), so automatically
skipping the instruction on kvm_emulate_*() makes sense:
1. rename kvm_emulate_halt() and kvm_emulate_wbinvd() to accommodate
callers that don't want to skip
2. introduce kvm_emulate_{halt,wbinvd}() and move the skip to to
kvm_emulate_{halt,wbinvd,hypercall}()
The alternative is to remove kvm_x86_ops->skip_emulated_instruction():
1. remove skip from kvm_emulate_cpuid() and modify callers
2. move kvm_complete_insn_gp to a header file and use
skip_emulated_instruction directly
3. remove unused kvm_x86_ops->skip_emulated_instruction()
Which one do you prefer?
Thanks.
next prev parent reply other threads:[~2015-03-02 16:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-28 0:19 [PATCH] x86: svm: make wbinvd faster Joel Schopp
2015-03-02 2:29 ` Bandan Das
2015-03-02 13:59 ` Radim Krčmář
2015-03-02 15:25 ` Bandan Das
2015-03-02 16:03 ` Radim Krčmář [this message]
2015-03-02 16:58 ` Joel Schopp
2015-03-02 14:09 ` Radim Krčmář
2015-03-09 23:28 ` Marcelo Tosatti
2015-03-10 11:01 ` Radim Krčmář
2015-03-10 22:37 ` Marcelo Tosatti
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