Re: [PATCH v5 1/2] KVM: SVM: Convert plain error code numbers to defines

Sean Christopherson
2025-02-25T22:28:48Z

On Tue, Feb 25, 2025, Melody Wang wrote:
> Convert VMGEXIT SW_EXITINFO1 codes from plain numbers to proper defines.
>
> No functionality changed.
>
> Signed-off-by: Melody Wang <huibo.wang@amd.com>
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> Reviewed-by: Pavan Kumar Paluri <papaluri@amd.com>
> ---
> arch/x86/include/asm/sev-common.h | 8 ++++++++
> arch/x86/kvm/svm/sev.c | 12 ++++++------
> arch/x86/kvm/svm/svm.c | 2 +-
> 3 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
> index dcbccdb280f9..3aca97d22cdc 100644
> --- a/arch/x86/include/asm/sev-common.h
> +++ b/arch/x86/include/asm/sev-common.h
> @@ -211,6 +211,14 @@ struct snp_psc_desc {
>
> #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)
>
> +/*
> + * Error codes of the GHCB SW_EXITINFO1 related to GHCB input that can be

The use of "Error codes" is confusing due to a psuedo-conflict with the below
comment for the "Error codes" for malformed input.

On that topic, the comment for _those_ error codes is a bad example, and shouldn't
be used as the basis for copy+paste. Most notably, it doesn't explicitly state
that the values are *defined* by the GHCB.

> + * communicated back to the guest
> + */
> +#define GHCB_HV_RESP_NO_ACTION 0
> +#define GHCB_HV_RESP_ISSUE_EXCEPTION 1
> +#define GHCB_HV_RESP_MALFORMED_INPUT 2
> +
> /*
> * Error codes related to GHCB input that can be communicated back to the guest
> * by setting the lower 32-bits of the GHCB SW_EXITINFO1 field to 2.

Now that GHCB_HV_RESP_MALFORMED_INPUT is properly defined, this comment can refer
to "malformed input (see above)" instead of open coding '2'.