On Mon, Sep 04, 2023 at 09:53:35AM +0000, Manali Shukla wrote: >There are four additional extended LVT registers available in extended >APIC register space which can be used for additional interrupt sources >like instruction based sampling and many more. > >Please refer to AMD programmers's manual Volume 2, Section 16.4.5 for >more details on extapic. >https://bugzilla.kernel.org/attachment.cgi?id=304653 > >Adds two new vcpu-based IOCTLs to save and restore the local APIC >registers with extended APIC register space for a single vcpu. It >works same as KVM_GET_LAPIC and KVM_SET_LAPIC IOCTLs. The only >differece is the size of APIC page which is copied/restored by kernel. >In case of KVM_GET_LAPIC_W_EXTAPIC and KVM_SET_LAPIC_W_EXTAPIC IOCTLs, >kernel copies/restores the APIC page with extended APIC register space >located at APIC offsets 400h-530h. > >KVM_GET_LAPIC_W_EXTAPIC and KVM_SET_LAPIC_W_EXTAPIC IOCTLs are used >when extended APIC is enabled in the guest. > >Document KVM_GET_LAPIC_W_EXTAPIC, KVM_SET_LAPIC_W_EXTAPIC ioctls. > >Signed-off-by: Manali Shukla <manali.shukla@xxxxxxx> >--- > Documentation/virt/kvm/api.rst | 23 +++++++++++++++++++++++ > arch/x86/include/uapi/asm/kvm.h | 5 +++++ > arch/x86/kvm/lapic.c | 12 +++++++----- > arch/x86/kvm/lapic.h | 6 ++++-- > arch/x86/kvm/x86.c | 24 +++++++++++++----------- > include/uapi/linux/kvm.h | 10 ++++++++++ > 6 files changed, 62 insertions(+), 18 deletions(-) > >diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst >index 73db30cb60fb..7239d4f1ecf3 100644 >--- a/Documentation/virt/kvm/api.rst >+++ b/Documentation/virt/kvm/api.rst >@@ -1961,6 +1961,18 @@ error. > Reads the Local APIC registers and copies them into the input argument. The > data format and layout are the same as documented in the architecture manual. > >+:: >+ >+ #define KVM_APIC_EXT_REG_SIZE 0x540 >+ struct kvm_lapic_state_w_extapic { >+ __u8 regs[KVM_APIC_EXT_REG_SIZE]; >+ }; The size of this new structure is also hard-coded. Do you think it is better to make the new structure extensible so that next time KVM needn't add more uAPIs for future local APIC extensions?
