From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.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
Subject: Re: [PATCH v2 3/3] KVM: x86: Move #PF retry tracking variables into emulation context
Date: Fri, 21 Feb 2020 10:28:13 -0800 [thread overview]
Message-ID: <20200221182813.GK12665@linux.intel.com> (raw)
In-Reply-To: <d5626891-82f6-0a0c-401c-89a901a8455d@redhat.com>
On Fri, Feb 21, 2020 at 06:14:03PM +0100, Paolo Bonzini wrote:
> On 19/02/20 16:16, Sean Christopherson wrote:
> > The easy solution to that is to move retry_instruction() into emulate.c.
> > That would also allow making x86_page_table_writing_insn() static. All
> > other functions invoked from retry_instruction() are exposed via kvm_host.h.
>
> emulate.c is supposed to invoke no (or almost no) function outside the
> ctxt->ops struct. In particular, retry_instruction() invokes
> kvm_mmu_gva_to_gpa_write and kvm_mmu_unprotect_page.
Ah, right. We could split the logic, e.g.
if (x86_retry_pf_instruction(ctxt, cr2_or_gpa, emulation_type)) {
gpa_t = gpa = cr2_or_gpa;
if (!vcpu->arch.mmu->direct_map)
gpa = kvm_mmu_gva_to_gpa_write(vcpu, cr2_or_gpa, NULL);
kvm_mmu_unprotect_page(vcpu->kvm, gpa_to_gfn(gpa));
return 1;
}
but that's probably a net negative in terms of clarity. And there's also
vcpu->arch.write_fault_to_shadow_pgtable, which is consumed only by
reexecute_instruction(), and I 100% agree that that variable should stay
in vcpu->arch. Moving one flag used to retry #PF instructions and not the
other would be weird.
That was a long winded way of saying I agree we should drop this patch :-)
prev parent reply other threads:[~2020-02-21 18:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 23:03 [PATCH v2 0/3] KVM: x86: Minor emulator cleanup Sean Christopherson
2020-02-18 23:03 ` [PATCH v2 1/3] KVM: x86: Add EMULTYPE_PF when emulation is triggered by a page fault Sean Christopherson
2020-02-19 9:01 ` Xiaoyao Li
2020-02-20 20:11 ` Sean Christopherson
2020-02-21 2:59 ` Xiaoyao Li
2020-02-21 17:12 ` Paolo Bonzini
2020-02-18 23:03 ` [PATCH v2 2/3] KVM: x86: Move gpa_val and gpa_available into the emulator context Sean Christopherson
2020-02-18 23:03 ` [PATCH v2 3/3] KVM: x86: Move #PF retry tracking variables into emulation context Sean Christopherson
2020-02-19 8:13 ` Paolo Bonzini
2020-02-19 15:16 ` Sean Christopherson
2020-02-21 17:14 ` Paolo Bonzini
2020-02-21 18:28 ` Sean Christopherson [this message]
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