Re: [PATCH 5/7] KVM: TDX: Handle TDG.VP.VMCALL<ReportFatalError>

[Binbin Wu]

On 12/6/2024 5:31 PM, Xu Yilun wrote:
> > +static int tdx_report_fatal_error(struct kvm_vcpu *vcpu)
> > +{
> > +	u64 reg_mask = kvm_rcx_read(vcpu);
> > +	u64* opt_regs;
> > +
> > +	/*
> > +	 * Skip sanity checks and let userspace decide what to do if sanity
> > +	 * checks fail.
> > +	 */
> > +	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> > +	vcpu->run->system_event.type = KVM_SYSTEM_EVENT_TDX_FATAL;
> > +	vcpu->run->system_event.ndata = 10;
> > +	/* Error codes. */
> > +	vcpu->run->system_event.data[0] = tdvmcall_a0_read(vcpu);
> > +	/* GPA of additional information page. */
> > +	vcpu->run->system_event.data[1] = tdvmcall_a1_read(vcpu);
> > +	/* Information passed via registers (up to 64 bytes). */
> > +	opt_regs = &vcpu->run->system_event.data[2];
> > +
> > +#define COPY_REG(REG, MASK)						\
> > +	do {								\
> > +		if (reg_mask & MASK)					\
> > +			*opt_regs = kvm_ ## REG ## _read(vcpu);		\
> > +		else							\
> > +			*opt_regs = 0;					\
> > +		opt_regs++;						\
> > +	} while (0)
> > +
> > +	/* The order is defined in GHCI. */
> > +	COPY_REG(r14, BIT_ULL(14));
> > +	COPY_REG(r15, BIT_ULL(15));
> > +	COPY_REG(rbx, BIT_ULL(3));
> > +	COPY_REG(rdi, BIT_ULL(7));
> > +	COPY_REG(rsi, BIT_ULL(6));
> > +	COPY_REG(r8, BIT_ULL(8));
> > +	COPY_REG(r9, BIT_ULL(9));
> > +	COPY_REG(rdx, BIT_ULL(2));
> Nit:
>
> #undef COPY_REG
Thanks for catching it!

> Thanks,
> Yilun
>
> > +
> > +	/*
> > +	 * Set the status code according to GHCI spec, although the vCPU may
> > +	 * not return back to guest.
> > +	 */
> > +	tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUCCESS);
> > +
> > +	/* Forward request to userspace. */
> > +	return 0;
> > +}