Re: [PATCH v2 07/11] KVM: x86: emulator/smm: add structs for KVM's smram layout

Maxim Levitsky
2022-07-21T11:54:15Z

On Thu, 2022-07-21 at 00:40 +0000, Sean Christopherson wrote:
> On Tue, Jun 21, 2022, Maxim Levitsky wrote:
> > Those structs will be used to read/write the smram state image.
> >
> > Also document the differences between KVM's SMRAM layout and SMRAM
> > layout that is used by real Intel/AMD cpus.
> >
> > Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> > ---
> > arch/x86/kvm/kvm_emulate.h | 139 +++++++++++++++++++++++++++++++++++++
> > 1 file changed, 139 insertions(+)
> >
> > diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
> > index 89246446d6aa9d..7015728da36d5f 100644
> > --- a/arch/x86/kvm/kvm_emulate.h
> > +++ b/arch/x86/kvm/kvm_emulate.h
> > @@ -503,6 +503,145 @@ enum x86_intercept {
> > nr_x86_intercepts
> > };
> >
> > +
> > +/*
> > + * 32 bit KVM's emulated SMM layout
> > + * Loosely based on Intel's layout
> > + */
> > +
> > +struct kvm_smm_seg_state_32 {
> > + u32 flags;
> > + u32 limit;
> > + u32 base;
> > +} __packed;
> > +
> > +struct kvm_smram_state_32 {
> > +
> > + u32 reserved1[62]; /* FE00 - FEF7 */
> > + u32 smbase; /* FEF8 */
> > + u32 smm_revision; /* FEFC */
> > + u32 reserved2[5]; /* FF00-FF13 */
> > + /* CR4 is not present in Intel/AMD SMRAM image*/
> > + u32 cr4; /* FF14 */
> > + u32 reserved3[5]; /* FF18 */
>
> Again, I love this approach, but we should have compile-time asserts to verify
> the layout, e.g. see vmx_check_vmcs12_offsets().
>

No objections, will do.

Best regards,
Maxim Levitsky