Re: [PATCH Part1 RFC v4 03/36] x86/sev: Add support for hypervisor feature VMGEXIT

Borislav Petkov
2021-08-10T11:21:50Z

On Wed, Jul 07, 2021 at 01:14:33PM -0500, Brijesh Singh wrote:
> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
> index 11b7d9cea775..23929a3010df 100644
> --- a/arch/x86/include/asm/sev-common.h
> +++ b/arch/x86/include/asm/sev-common.h
> @@ -45,6 +45,15 @@
> (((unsigned long)reg & GHCB_MSR_CPUID_REG_MASK) << GHCB_MSR_CPUID_REG_POS) | \
> (((unsigned long)fn) << GHCB_MSR_CPUID_FUNC_POS))
>
> +/* GHCB Hypervisor Feature Request */
> +#define GHCB_MSR_HV_FT_REQ 0x080
> +#define GHCB_MSR_HV_FT_RESP 0x081
> +#define GHCB_MSR_HV_FT_POS 12
> +#define GHCB_MSR_HV_FT_MASK GENMASK_ULL(51, 0)
> +
> +#define GHCB_MSR_HV_FT_RESP_VAL(v) \
> + (((unsigned long)((v) >> GHCB_MSR_HV_FT_POS) & GHCB_MSR_HV_FT_MASK))

As I suggested...

> @@ -215,6 +216,7 @@
> { SVM_VMGEXIT_NMI_COMPLETE, "vmgexit_nmi_complete" }, \
> { SVM_VMGEXIT_AP_HLT_LOOP, "vmgexit_ap_hlt_loop" }, \
> { SVM_VMGEXIT_AP_JUMP_TABLE, "vmgexit_ap_jump_table" }, \
> + { SVM_VMGEXIT_HYPERVISOR_FEATURES, "vmgexit_hypervisor_feature" }, \

SVM_VMGEXIT_HV_FEATURES

> { SVM_EXIT_ERR, "invalid_guest_state" }
>
>
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 19c2306ac02d..34821da5f05e 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -23,6 +23,9 @@
> */
> static u16 ghcb_version __section(".data..ro_after_init");
>
> +/* Bitmap of SEV features supported by the hypervisor */
> +u64 sev_hv_features __section(".data..ro_after_init") = 0;

__ro_after_init

> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 66b7f63ad041..540b81ac54c9 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -96,6 +96,9 @@ struct ghcb_state {
> static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
> DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
>
> +/* Bitmap of SEV features supported by the hypervisor */
> +EXPORT_SYMBOL(sev_hv_features);

Why is this exported and why not a _GPL export?

--
Regards/Gruss,
Boris.