| Message ID | 1399336859-7227-3-git-send-email-bsd@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 06/05/2014 02:40, Bandan Das ha scritto: > Insn fetch fastpath function. Not that > arch.walk_mmu->gva_to_gpa can't be used but let's > piggyback on top of interface meant for our purpose > > Signed-off-by: Bandan Das <bsd@redhat.com> > --- > arch/x86/kvm/x86.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 17e3d661..cf69e3b 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4065,29 +4065,38 @@ static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes, > struct x86_exception *exception) > { > void *data = val; > - struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); > int r = X86EMUL_CONTINUE; > > while (bytes) { > - gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access, > - exception); > unsigned offset = addr & (PAGE_SIZE-1); > unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset); > int ret; > + unsigned long uaddr; > > - if (gpa == UNMAPPED_GVA) > - return X86EMUL_PROPAGATE_FAULT; > - ret = kvm_read_guest(vcpu->kvm, gpa, data, toread); > + ret = ctxt->ops->memory_prepare(ctxt, addr, toread, > + exception, false, > + NULL, &uaddr); You can call the function from x86.c directly, no need to go through ctxt->ops. > + if (ret != X86EMUL_CONTINUE) > + return ret; > + > + if (unlikely(kvm_is_error_hva(uaddr))) { > + r = X86EMUL_PROPAGATE_FAULT; > + return r; > + } > + > + ret = __copy_from_user(data, (void __user *)uaddr, toread); > if (ret < 0) { > r = X86EMUL_IO_NEEDED; > - goto out; > + return r; > } > > + ctxt->ops->memory_finish(ctxt, NULL, uaddr); No need to call memory_finish, since you know the implementation (perhaps add a comment). Paolo > bytes -= toread; > data += toread; > addr += toread; > } > -out: > + > return r; > } > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Il 06/05/2014 02:40, Bandan Das ha scritto: > + ret = ctxt->ops->memory_prepare(ctxt, addr, toread, > + exception, false, > + NULL, &uaddr); > + if (ret != X86EMUL_CONTINUE) > + return ret; > + > + if (unlikely(kvm_is_error_hva(uaddr))) { > + r = X86EMUL_PROPAGATE_FAULT; > + return r; > + } What you are doing here is basically optimizing kvm_read_guest_virt_helper because you know that all reads will be single-page and you do not need the "next_segment" in kvm_read_guest. Good catch, but you can use kvm_read_guest_page instead of going through ctxt->ops->memory_prepare. :) Paolo > + ret = __copy_from_user(data, (void __user *)uaddr, toread); -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 17e3d661..cf69e3b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4065,29 +4065,38 @@ static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes, struct x86_exception *exception) { void *data = val; - struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); int r = X86EMUL_CONTINUE; while (bytes) { - gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access, - exception); unsigned offset = addr & (PAGE_SIZE-1); unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset); int ret; + unsigned long uaddr; - if (gpa == UNMAPPED_GVA) - return X86EMUL_PROPAGATE_FAULT; - ret = kvm_read_guest(vcpu->kvm, gpa, data, toread); + ret = ctxt->ops->memory_prepare(ctxt, addr, toread, + exception, false, + NULL, &uaddr); + if (ret != X86EMUL_CONTINUE) + return ret; + + if (unlikely(kvm_is_error_hva(uaddr))) { + r = X86EMUL_PROPAGATE_FAULT; + return r; + } + + ret = __copy_from_user(data, (void __user *)uaddr, toread); if (ret < 0) { r = X86EMUL_IO_NEEDED; - goto out; + return r; } + ctxt->ops->memory_finish(ctxt, NULL, uaddr); + bytes -= toread; data += toread; addr += toread; } -out: + return r; }
Insn fetch fastpath function. Not that arch.walk_mmu->gva_to_gpa can't be used but let's piggyback on top of interface meant for our purpose Signed-off-by: Bandan Das <bsd@redhat.com> --- arch/x86/kvm/x86.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)