On Thu, Mar 17, 2022 at 09:58:45PM +0800,
Xiaoyao Li wrote:
> For TDX, the allowable CPUID configuration differs from what KVM
> reports for KVM scope via KVM_GET_SUPPORTED_CPUID.
>
> - Some CPUID bits are not supported for TDX VM while KVM reports the
> support. Mask them off for TDX VM. e.g., CPUID_EXT_VMX, some PV
> featues.
>
> - The supported XCR0 and XSS bits needs to be caped by tdx_caps, because
> KVM uses them to setup XFAM of TD.
>
> Introduce tdx_get_supported_cpuid() to adjust the
> kvm_arch_get_supported_cpuid() for TDX VM.
>
> Signed-off-by: Xiaoyao Li
> ---
> target/i386/cpu.h | 5 +
> target/i386/kvm/kvm.c | 4
> target/i386/kvm/tdx.c | 39 +++
> target/i386/kvm/tdx.h | 2 ++
> 4 files changed, 50 insertions(+)
>
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 5e406088a91a..7fa30f4ed7db 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -566,6 +566,11 @@ typedef enum X86Seg {
> #define ESA_FEATURE_XFD_MASK(1U << ESA_FEATURE_XFD_BIT)
>
>
> +#define XCR0_MASK (XSTATE_FP_MASK | XSTATE_SSE_MASK | XSTATE_YMM_MASK
> | \
> + XSTATE_BNDREGS_MASK | XSTATE_BNDCSR_MASK | \
> + XSTATE_OPMASK_MASK | XSTATE_ZMM_Hi256_MASK | \
> + XSTATE_Hi16_ZMM_MASK | XSTATE_PKRU_MASK)
> +
> /* CPUID feature words */
> typedef enum FeatureWord {
> FEAT_1_EDX, /* CPUID[1].EDX */
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 26ed5faf07b8..ddbe8f64fadb 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -486,6 +486,10 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s,
> uint32_t function,
> ret |= 1U << KVM_HINTS_REALTIME;
> }
>
> +if (is_tdx_vm()) {
> +tdx_get_supported_cpuid(function, index, reg, &ret);
> +}
> +
> return ret;
> }
>
> diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
> index 846511b299f4..e4ee55f30c79 100644
> --- a/target/i386/kvm/tdx.c
> +++ b/target/i386/kvm/tdx.c
> @@ -14,6 +14,7 @@
> #include "qemu/osdep.h"
> #include "qapi/error.h"
> #include "qom/object_interfaces.h"
> +#include "standard-headers/asm-x86/kvm_para.h"
> #include "sysemu/kvm.h"
>
> #include "hw/i386/x86.h"
> @@ -110,6 +111,44 @@ int tdx_kvm_init(MachineState *ms, Error **errp)
> return 0;
> }
>
> +void tdx_get_supported_cpuid(uint32_t function, uint32_t index, int reg,
> + uint32_t *ret)
> +{
> +switch (function) {
> +case 1:
> +if (reg == R_ECX) {
> +*ret &= ~CPUID_EXT_VMX;
> +}
> +break;
> +case 0xd:
> +if (index == 0) {
> +if (reg == R_EAX) {
> +*ret &= (uint32_t)tdx_caps->xfam_fixed0 & XCR0_MASK;
> +*ret |= (uint32_t)tdx_caps->xfam_fixed1 & XCR0_MASK;
> +} else if (reg == R_EDX) {
> +*ret &= (tdx_caps->xfam_fixed0 & XCR0_MASK) >> 32;
> +*ret |= (tdx_caps->xfam_fixed1 & XCR0_MASK) >> 32;
> +}
> +} else if (index == 1) {
> +/* TODO: Adjust XSS when it's supported. */
> +}
> +break;
> +case KVM_CPUID_FEATURES:
> +if (reg == R_EAX) {
> +*ret &= ~((1ULL << KVM_FEATURE_CLOCKSOURCE) |
> + (1ULL << KVM_FEATURE_CLOCKSOURCE2) |
> + (1ULL << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
> + (1ULL << KVM_FEATURE_ASYNC_PF) |
> + (1ULL << KVM_FEATURE_ASYNC_PF_VMEXIT) |
> + (1ULL << KVM_FEATURE_ASYNC_PF_INT));
Because new feature bit may be introduced in future (it's unlikely though),
*ret &= (supported_bits) is better than *ret &= ~(unsupported_bits)
Thanks,
> +}
> +break;
> +default:
> +/* TODO: Use tdx_caps to adjust CPUID leafs. */
> +break;
> +}
> +}
> +
> /* tdx guest */
> OBJECT_DEFINE_TYPE_WITH_INTERFACES(TdxGuest,
> tdx_guest,
> diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
> index 4036ca2f3f99..06599b65b827 100644
> --- a/target/i386/kvm/tdx.h
> +++ b/target/i386/kvm/tdx.h
> @@ -27,5 +27,7 @@ bool is_tdx_vm(void);
> #endif /* CONFIG_TDX */
>
> int tdx_kvm_init(MachineState *ms, Error **errp);
> +void tdx_get_supported_cpuid(uint32_t function, uint32_t index, int reg,
> + uint32_t *ret);
>
> #endif /* QEMU_I386_TDX_H */
> --
> 2.27.0
>
>
--
Isaku Yamahata
