On Mon, May 13, 2024 at 12:05:35PM -0500, Michael Roth wrote:
> On Mon, May 13, 2024 at 06:53:24PM +0200, Paolo Bonzini wrote:
> > On 5/13/24 17:19, Nathan Chancellor wrote:
> > > > +static int snp_begin_ext_guest_req(struct kvm_vcpu *vcpu)
> > > > +{
> > > > + int vmm_ret = SNP_GUEST_VMM_ERR_GENERIC;
> > > > + struct vcpu_svm *svm = to_svm(vcpu);
> > > > + unsigned long data_npages;
> > > > + sev_ret_code fw_err;
> > > > + gpa_t data_gpa;
> > > > +
> > > > + if (!sev_snp_guest(vcpu->kvm))
> > > > + goto abort_request;
> > > > +
> > > > + data_gpa = vcpu->arch.regs[VCPU_REGS_RAX];
> > > > + data_npages = vcpu->arch.regs[VCPU_REGS_RBX];
> > > > +
> > > > + if (!IS_ALIGNED(data_gpa, PAGE_SIZE))
> > > > + goto abort_request;
> > >
> > > [...]
> > >
> > > > +abort_request:
> > > > + ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(vmm_ret, fw_err));
> > > > + return 1; /* resume guest */
> > > > +}
> > >
> > > This patch is now in -next as commit 32fde9e18b3f ("KVM: SEV: Provide
> > > support for SNP_EXTENDED_GUEST_REQUEST NAE event"), where it causes a
> > > clang warning (or hard error when CONFIG_WERROR is enabled) [...]
> > > Seems legitimate to me. What was the intention here?
> >
> > Mike, I think this should just be 0?
>
> Hi Paolo,
>
> Yes, I was just about to submit a patch that does just that:
>
> https://github.com/mdroth/linux/commit/df55e9c5b97542fe037f5b5293c11a49f7c658ef
Submitted a proper patch here:
https://lore.kernel.org/kvm/20240513172704.718533-1-michael.roth@xxxxxxx/
and also one for a separate warning:
https://lore.kernel.org/kvm/20240513181928.720979-1-michael.roth@xxxxxxx/
I saw my build environment had WARN=0 for the last round of changes, so I
re-tested various kernel configs with/without clang and haven't seen any
other issues. So I think that should be the last of it. I'll be sure to be
a lot more careful about this in the future.
Thanks,
Mike
>
> Sorry for the breakage,
>
> Mike
>
> >
> > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > index c7a0971149f2..affb4fb47f91 100644
> > --- a/arch/x86/kvm/svm/sev.c
> > +++ b/arch/x86/kvm/svm/sev.c
> > @@ -3911,7 +3911,6 @@ static int snp_begin_ext_guest_req(struct kvm_vcpu *vcpu)
> > int vmm_ret = SNP_GUEST_VMM_ERR_GENERIC;
> > struct vcpu_svm *svm = to_svm(vcpu);
> > unsigned long data_npages;
> > - sev_ret_code fw_err;
> > gpa_t data_gpa;
> > if (!sev_snp_guest(vcpu->kvm))
> > @@ -3938,7 +3937,7 @@ static int snp_begin_ext_guest_req(struct kvm_vcpu *vcpu)
> > return 0; /* forward request to userspace */
> > abort_request:
> > - ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(vmm_ret, fw_err));
> > + ghcb_set_sw_exit_info_2(svm->sev_es.ghcb, SNP_GUEST_ERR(vmm_ret, 0));
> > return 1; /* resume guest */
> > }
> > Paolo
> >
> >
>
