On Thu, Oct 31, 2024 at 05:09:17PM +0800, Binbin Wu wrote:
>
>
>
> On 10/31/2024 3:00 AM, Rick Edgecombe wrote:
> [...]
> > +static u32 tdx_set_guest_phys_addr_bits(const u32 eax, int addr_bits)
> > +{
> > + return (eax & ~GENMASK(23, 16)) | (addr_bits & 0xff) << 16;
> > +}
> > +
> > +#define KVM_TDX_CPUID_NO_SUBLEAF ((__u32)-1)
> > +
> > +static void td_init_cpuid_entry2(struct kvm_cpuid_entry2 *entry, unsigned char idx)
> > +{
> > + const struct tdx_sys_info_td_conf *td_conf = &tdx_sysinfo->td_conf;
> > +
> > + entry->function = (u32)td_conf->cpuid_config_leaves[idx];
> > + entry->index = td_conf->cpuid_config_leaves[idx] >> 32;
> > + entry->eax = (u32)td_conf->cpuid_config_values[idx][0];
> > + entry->ebx = td_conf->cpuid_config_values[idx][0] >> 32;
> > + entry->ecx = (u32)td_conf->cpuid_config_values[idx][1];
> > + entry->edx = td_conf->cpuid_config_values[idx][1] >> 32;
> > +
> > + if (entry->index == KVM_TDX_CPUID_NO_SUBLEAF)
> > + entry->index = 0;
> > +
> > + /* Work around missing support on old TDX modules */
> > + if (entry->function == 0x80000008)
> > + entry->eax = tdx_set_guest_phys_addr_bits(entry->eax, 0xff);
> Is it necessary to set bit 16~23 to 0xff?
> It seems that when userspace wants to retrieve the value, the GPAW will
> be set in tdx_read_cpuid() anyway.
Leaving it out currently produces:
qemu-system-x86_64: KVM_TDX_INIT_VM failed: Invalid argument
Regards,
Tony
