On 5/20/21 11:02 AM, Borislav Petkov wrote:
> On Fri, Apr 30, 2021 at 07:16:05AM -0500, Brijesh Singh wrote:
>> diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
>> index 6d9055427f37..7badbeb6cb95 100644
>> --- a/arch/x86/boot/compressed/sev.c
>> +++ b/arch/x86/boot/compressed/sev.c
>> @@ -25,6 +25,8 @@
>>
>> struct ghcb boot_ghcb_page __aligned(PAGE_SIZE);
>> struct ghcb *boot_ghcb;
>> +static u64 sev_status_val;
> msr_sev_status should be more descriptive.
Noted.
>
>> +static bool sev_status_checked;
> You don't need this one - you can simply do
>
> if (!msr_sev_status)
> read the MSR.
Agreed.
>
>> /*
>> * Copy a version of this function here - insn-eval.c can't be used in
>> @@ -119,11 +121,30 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
>> /* Include code for early handlers */
>> #include "../../kernel/sev-shared.c"
>>
>> +static inline bool sev_snp_enabled(void)
>> +{
>> + unsigned long low, high;
>> +
>> + if (!sev_status_checked) {
>> + asm volatile("rdmsr\n"
>> + : "=a" (low), "=d" (high)
>> + : "c" (MSR_AMD64_SEV));
>> + sev_status_val = (high << 32) | low;
>> + sev_status_checked = true;
>> + }
>> +
>> + return sev_status_val & MSR_AMD64_SEV_SNP_ENABLED ? true : false;
> return msr_sev_status & MSR_AMD64_SEV_SNP_ENABLED;
>
> is enough.
Noted.
>> +}
>> +
>> static bool early_setup_sev_es(void)
>> {
>> if (!sev_es_negotiate_protocol())
>> sev_es_terminate(0, GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED);
>>
>> + /* If SEV-SNP is enabled then check if the hypervisor supports the SEV-SNP features. */
> 80 cols like the rest of this file pls.
Noted.
>
>> + if (sev_snp_enabled() && !sev_snp_check_hypervisor_features())
>> + sev_es_terminate(0, GHCB_SEV_ES_REASON_SNP_UNSUPPORTED);
>> +
>> if (set_page_decrypted((unsigned long)&boot_ghcb_page))
>> return false;
> Thx.
>
