Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1714655

Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when gpa_available is set

From David Hildenbrand <david@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when gpa_available is set
Date 2017-08-18 10:00 +0200
Message-ID <ufKme-tm-3@gated-at.bofh.it> (permalink)
References <ufvZU-7qv-15@gated-at.bofh.it> <ufvZU-7qv-13@gated-at.bofh.it>
Organization Red Hat GmbH

Show all headers | View raw

> +++ b/arch/x86/kvm/x86.c
> @@ -4657,25 +4657,18 @@ static int emulator_read_write_onepage(unsigned long addr, void *val,
>  	 */
>  	if (vcpu->arch.gpa_available &&
>  	    emulator_can_use_gpa(ctxt) &&
> -	    vcpu_is_mmio_gpa(vcpu, addr, exception->address, write) &&
> -	    (addr & ~PAGE_MASK) == (exception->address & ~PAGE_MASK)) {
> -		gpa = exception->address;
> -		goto mmio;
> +	    (addr & ~PAGE_MASK) == (vcpu->arch.gpa_val & ~PAGE_MASK)) {
> +		gpa = vcpu->arch.gpa_val;
> +		ret = vcpu_is_mmio_gpa(vcpu, addr, gpa, write);
> +	} else {
> +		ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write);
>  	}
>  
> -	ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write);
> -
>  	if (ret < 0)
>  		return X86EMUL_PROPAGATE_FAULT;

just wondering if it makes sense to move this into the else branch (as
it logically only belongs to vcpu_mmio_gva_to_gpa)

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 

Thanks,

David

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 2/3] KVM: x86: Avoid guest page table walk when gpa_available is set Paolo Bonzini <pbonzini@redhat.com> - 2017-08-17 18:40 +0200
  Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when  gpa_available is set David Hildenbrand <david@redhat.com> - 2017-08-18 10:00 +0200
    Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when  gpa_available is set Radim Krčmář <rkrcmar@redhat.com> - 2017-08-18 14:40 +0200
      Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when  gpa_available is set Paolo Bonzini <pbonzini@redhat.com> - 2017-08-18 14:40 +0200
        Re: [PATCH 2/3] KVM: x86: Avoid guest page table walk when  gpa_available is set Radim Krčmář <rkrcmar@redhat.com> - 2017-08-18 14:50 +0200

csiph-web