Re: [RFC PATCH v4 05/18] kvm: x86: add kvm_arch_vcpu_set_regs()

[alazar@bitdefender.com]

On Thu, 21 Dec 2017 16:39:02 -0500, Patrick Colp <patrick.colp@oracle.com> wrote:
> On 2017-12-18 02:06 PM, Adalber Lazăr wrote:
> > From: Adalbert Lazar <alazar@bitdefender.com>
> > 
> > This is a version of kvm_arch_vcpu_ioctl_set_regs() which does not touch
> > the exceptions vector.
> > 
> > Signed-off-by: Mihai Donțu <mdontu@bitdefender.com>
> > ---
> >   arch/x86/kvm/x86.c       | 34 ++++++++++++++++++++++++++++++++++
> >   include/linux/kvm_host.h |  1 +
> >   2 files changed, 35 insertions(+)
> > 
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index e1a3c2c6ec08..4b0c3692386d 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -7389,6 +7389,40 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> >   	return 0;
> >   }
> >   
> > +/*
> > + * Similar to kvm_arch_vcpu_ioctl_set_regs() but it does not reset
> > + * the exceptions
> > + */
> > +void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> > +{
> > +	vcpu->arch.emulate_regs_need_sync_from_vcpu = true;
> > +	vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
> > +
> > +	kvm_register_write(vcpu, VCPU_REGS_RAX, regs->rax);
> > +	kvm_register_write(vcpu, VCPU_REGS_RBX, regs->rbx);
> > +	kvm_register_write(vcpu, VCPU_REGS_RCX, regs->rcx);
> > +	kvm_register_write(vcpu, VCPU_REGS_RDX, regs->rdx);
> > +	kvm_register_write(vcpu, VCPU_REGS_RSI, regs->rsi);
> > +	kvm_register_write(vcpu, VCPU_REGS_RDI, regs->rdi);
> > +	kvm_register_write(vcpu, VCPU_REGS_RSP, regs->rsp);
> > +	kvm_register_write(vcpu, VCPU_REGS_RBP, regs->rbp);
> > +#ifdef CONFIG_X86_64
> > +	kvm_register_write(vcpu, VCPU_REGS_R8, regs->r8);
> > +	kvm_register_write(vcpu, VCPU_REGS_R9, regs->r9);
> > +	kvm_register_write(vcpu, VCPU_REGS_R10, regs->r10);
> > +	kvm_register_write(vcpu, VCPU_REGS_R11, regs->r11);
> > +	kvm_register_write(vcpu, VCPU_REGS_R12, regs->r12);
> > +	kvm_register_write(vcpu, VCPU_REGS_R13, regs->r13);
> > +	kvm_register_write(vcpu, VCPU_REGS_R14, regs->r14);
> > +	kvm_register_write(vcpu, VCPU_REGS_R15, regs->r15);
> > +#endif
> > +
> > +	kvm_rip_write(vcpu, regs->rip);
> > +	kvm_set_rflags(vcpu, regs->rflags);
> > +
> > +	kvm_make_request(KVM_REQ_EVENT, vcpu);
> > +}
> > +
> 
> kvm_arch_vcpu_ioctl_set_regs() returns an int (so that, for e.g., in ARM 
> it can return an error to indicate that the function is not 
> supported/implemented). Is there a reason this function shouldn't do the 
> same (is it only ever going to be implemented for x86)?
> 
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index 6bdd4b9f6611..68e4d756f5c9 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -767,6 +767,7 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
> >   
> >   int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
> >   int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
> > +void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
> >   int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
> >   				  struct kvm_sregs *sregs);
> 
> 
> Patrick

\x13Hi Patrick,

Thank you for taking the time to review these patches.

You're right. This function should return an error code, regardless on
the time \x12\x12\x12\x12when ARM will be supported.

Adalbert

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