lkml.org 
[lkml]   [2022]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH v8 29/40] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers
    On Mon, Jan 17, 2022 at 10:35:21PM -0600, Michael Roth wrote:
    > Unfortunately, in sev_enable(), between the point where snp_init() is
    > called, and sev_status is actually set, there are a number of cpuid
    > intructions which will make use of do_vc_no_ghcb() prior to sev_status
    > being set (and it needs to happen in that order to set sev_status
    > appropriately). After that point, snp_cpuid_active() would no longer be
    > necessary, but during that span some indicator is needed in case this
    > is just an SEV-ES guest trigger cpuid #VCs.

    You mean testing what snp_cpuid_info_create() set up is not enough?

    diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
    index 7bc7e297f88c..17cfe804bad3 100644
    --- a/arch/x86/kernel/sev-shared.c
    +++ b/arch/x86/kernel/sev-shared.c
    @@ -523,7 +523,9 @@ static int snp_cpuid_postprocess(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
    static int snp_cpuid(u32 func, u32 subfunc, u32 *eax, u32 *ebx, u32 *ecx,
    u32 *edx)
    {
    - if (!snp_cpuid_active())
    + const struct snp_cpuid_info *c = snp_cpuid_info_get_ptr();
    +
    + if (!c->count)
    return -EOPNOTSUPP;

    if (!snp_cpuid_find_validated_func(func, subfunc, eax, ebx, ecx, edx)) {
    ---
    Btw, all those

    /* SEV-SNP CPUID table should be set up now. */
    if (!snp_cpuid_active())
    sev_es_terminate(1, GHCB_TERM_CPUID);
    after snp_cpuid_info_create() has returned are useless either. If that
    function returns, you know you're good to go wrt SNP.

    Thx.

    --
    Regards/Gruss,
    Boris.

    https://people.kernel.org/tglx/notes-about-netiquette

    \
     
     \ /
      Last update: 2022-01-18 15:03    [W:6.166 / U:1.256 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site