On 6/17/2019 10:56 AM, Liran Alon wrote:
> Improve the KVM_{GET,SET}_NESTED_STATE structs by detailing the format
> of VMX nested state data in a struct.
>
> In order to avoid changing the ioctl values of
> KVM_{GET,SET}_NESTED_STATE, there is a need to preserve
> sizeof(struct kvm_nested_state). This is done by defining the data
> struct as "data.vmx[0]". It was the most elegant way I found to
> preserve struct size while still keeping struct readable and easy to
> maintain. It does have a misfortunate side-effect that now it has to be
> accessed as "data.vmx[0]" rather than just "data.vmx".
>
> Because we are already modifying these structs, I also modified the
> following:
> * Define the "format" field values as macros.
> * Rename vmcs_pa to vmcs12_pa for better readability.
> * Add stub structs for AMD SVM.
>
> Signed-off-by: Liran Alon <liran.alon@oracle.com>
> ---
> linux-headers/asm-x86/kvm.h | 41 +++++++++++++++++++++++++++----------
> 1 file changed, 30 insertions(+), 11 deletions(-)
>
> diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
> index 7a0e64ccd6ff..e655d108af19 100644
> --- a/linux-headers/asm-x86/kvm.h
> +++ b/linux-headers/asm-x86/kvm.h
> @@ -383,6 +383,9 @@ struct kvm_sync_regs {
> #define KVM_X86_QUIRK_LAPIC_MMIO_HOLE (1 << 2)
> #define KVM_X86_QUIRK_OUT_7E_INC_RIP (1 << 3)
>
> +#define KVM_STATE_NESTED_FORMAT_VMX 0
> +#define KVM_STATE_NESTED_FORMAT_SVM 1
> +
> #define KVM_STATE_NESTED_GUEST_MODE 0x00000001
> #define KVM_STATE_NESTED_RUN_PENDING 0x00000002
> #define KVM_STATE_NESTED_EVMCS 0x00000004
> @@ -390,35 +393,51 @@ struct kvm_sync_regs {
> #define KVM_STATE_NESTED_SMM_GUEST_MODE 0x00000001
> #define KVM_STATE_NESTED_SMM_VMXON 0x00000002
>
> -struct kvm_vmx_nested_state {
> +struct kvm_vmx_nested_state_data {
> + __u8 vmcs12[0x1000];
> + __u8 shadow_vmcs12[0x1000];
I assume you will replace this magic 0x1000 value too, as discussed with
respect to patch 7?
Thanks,
-Maran
> +};
> +
> +struct kvm_vmx_nested_state_hdr {
> __u64 vmxon_pa;
> - __u64 vmcs_pa;
> + __u64 vmcs12_pa;
>
> struct {
> __u16 flags;
> } smm;
> };
>
> +struct kvm_svm_nested_state_data {
> + /* TODO: Implement */
> +};
> +
> +struct kvm_svm_nested_state_hdr {
> + /* TODO: Implement */
> +};
> +
> /* for KVM_CAP_NESTED_STATE */
> struct kvm_nested_state {
> - /* KVM_STATE_* flags */
> __u16 flags;
> -
> - /* 0 for VMX, 1 for SVM. */
> __u16 format;
> -
> - /* 128 for SVM, 128 + VMCS size for VMX. */
> __u32 size;
>
> union {
> - /* VMXON, VMCS */
> - struct kvm_vmx_nested_state vmx;
> + struct kvm_vmx_nested_state_hdr vmx;
> + struct kvm_svm_nested_state_hdr svm;
>
> /* Pad the header to 128 bytes. */
> __u8 pad[120];
> - };
> + } hdr;
>
> - __u8 data[0];
> + /*
> + * Define data region as 0 bytes to preserve backwards-compatability
> + * to old definition of kvm_nested_state in order to avoid changing
> + * KVM_{GET,PUT}_NESTED_STATE ioctl values.
> + */
> + union {
> + struct kvm_vmx_nested_state_data vmx[0];
> + struct kvm_svm_nested_state_data svm[0];
> + } data;
> };
>
> #endif /* _ASM_X86_KVM_H */