On Mon, Jan 16, 2023 at 10:04:19AM +0000,
"Huang, Kai" <kai.huang@xxxxxxxxx> wrote:
> On Thu, 2023-01-12 at 08:31 -0800, isaku.yamahata@xxxxxxxxx wrote:
> > +struct kvm_tdx_init_vm {
> > + __u64 attributes;
> > + __u64 mrconfigid[6]; /* sha384 digest */
> > + __u64 mrowner[6]; /* sha384 digest */
> > + __u64 mrownerconfig[6]; /* sha348 digest */
> > + union {
> > + /*
> > + * KVM_TDX_INIT_VM is called before vcpu creation, thus before
> > + * KVM_SET_CPUID2. CPUID configurations needs to be passed.
> > + *
> > + * This configuration supersedes KVM_SET_CPUID{,2}.
>
> What does "{,2}" mean?
Both KVM_SET_CPUID and KVM_SET_CPUID2. For comment purpose, only KVM_SET_CPUID2
suffice. I'll drop "{,2}".
>
> > + * The user space VMM, e.g. qemu, should make them consistent
> > + * with this values.
>
> You are already using 'struct kvm_cpuid2' below. Isn't it enough to imply that
> userspace should organize data in the format of 'struct kvm_cpuid2'?
>
> > + * sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES(256)
> > + * = 8KB.
> > + */
>
> What does this comment try to imply?
>
> > + struct {
> > + struct kvm_cpuid2 cpuid;
> > + /* 8KB with KVM_MAX_CPUID_ENTRIES. */
> > + struct kvm_cpuid_entry2 entries[];
>
> I don't understand what's the purpose of the second field?
>
> Shouldn't the 'struct kvm_cpuid2' already have all the CPUID entries?
>
> > + };
> > + /*
> > + * For future extensibility.
> > + * The size(struct kvm_tdx_init_vm) = 16KB.
> > + * This should be enough given sizeof(TD_PARAMS) = 1024
> > + */
> > + __u64 reserved[2029];
>
> I think this is just wrong. How can you extend something after a dynamic size
> CPUID array?
>
> If you want extensibility, you need to put the space before the flexible array.
>
> > + };
> > +};
I changed the struct as follows.
struct kvm_tdx_init_vm {
__u64 attributes;
__u64 mrconfigid[6]; /* sha384 digest */
__u64 mrowner[6]; /* sha384 digest */
__u64 mrownerconfig[6]; /* sha348 digest */
/*
* For future extensibility to make sizeof(struct kvm_tdx_init_vm) = 8KB.
* This should be enough given sizeof(TD_PARAMS) = 1024.
* 8KB was chosen given because
* sizeof(struct kvm_cpuid_entry2) * KVM_MAX_CPUID_ENTRIES(=256) = 8KB.
*/
__u64 reserved[1004];
/*
* KVM_TDX_INIT_VM is called before vcpu creation, thus before
* KVM_SET_CPUID2.
* This configuration supersedes KVM_SET_CPUID2s for VCPUs. The user
* space VMM, e.g. qemu, should make KVM_SET_CPUID2 consistent with this
* values.
*/
struct kvm_cpuid2 cpuid;
};
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
