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    Subject[PATCH v5 06/14] x86/sev: Cache the secrets page address
    Date
    Save the secrets page address during snp_init() from the CC blob. Use
    secrets_pa instead of calling get_secrets_page() that remaps the CC
    blob for getting the secrets page every time.

    Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
    Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
    ---
    arch/x86/kernel/sev.c | 52 +++++++++++++------------------------------
    1 file changed, 16 insertions(+), 36 deletions(-)

    diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
    index f8caf0a73052..fd3b822fa9e7 100644
    --- a/arch/x86/kernel/sev.c
    +++ b/arch/x86/kernel/sev.c
    @@ -72,6 +72,9 @@ static struct ghcb *boot_ghcb __section(".data");
    /* Bitmap of SEV features supported by the hypervisor */
    static u64 sev_hv_features __ro_after_init;

    +/* Secrets page physical address from the CC blob */
    +static u64 secrets_pa __ro_after_init;
    +
    /* #VC handler runtime per-CPU data */
    struct sev_es_runtime_data {
    struct ghcb ghcb_page;
    @@ -598,45 +601,16 @@ void noinstr __sev_es_nmi_complete(void)
    __sev_put_ghcb(&state);
    }

    -static u64 __init get_secrets_page(void)
    -{
    - u64 pa_data = boot_params.cc_blob_address;
    - struct cc_blob_sev_info info;
    - void *map;
    -
    - /*
    - * The CC blob contains the address of the secrets page, check if the
    - * blob is present.
    - */
    - if (!pa_data)
    - return 0;
    -
    - map = early_memremap(pa_data, sizeof(info));
    - if (!map) {
    - pr_err("Unable to locate SNP secrets page: failed to map the Confidential Computing blob.\n");
    - return 0;
    - }
    - memcpy(&info, map, sizeof(info));
    - early_memunmap(map, sizeof(info));
    -
    - /* smoke-test the secrets page passed */
    - if (!info.secrets_phys || info.secrets_len != PAGE_SIZE)
    - return 0;
    -
    - return info.secrets_phys;
    -}
    -
    static u64 __init get_snp_jump_table_addr(void)
    {
    struct snp_secrets_page_layout *layout;
    void __iomem *mem;
    - u64 pa, addr;
    + u64 addr;

    - pa = get_secrets_page();
    - if (!pa)
    + if (!secrets_pa)
    return 0;

    - mem = ioremap_encrypted(pa, PAGE_SIZE);
    + mem = ioremap_encrypted(secrets_pa, PAGE_SIZE);
    if (!mem) {
    pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
    return 0;
    @@ -2083,6 +2057,12 @@ static __init struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
    return cc_info;
    }

    +static void __init set_secrets_pa(const struct cc_blob_sev_info *cc_info)
    +{
    + if (cc_info && cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE)
    + secrets_pa = cc_info->secrets_phys;
    +}
    +
    bool __init snp_init(struct boot_params *bp)
    {
    struct cc_blob_sev_info *cc_info;
    @@ -2094,6 +2074,8 @@ bool __init snp_init(struct boot_params *bp)
    if (!cc_info)
    return false;

    + set_secrets_pa(cc_info);
    +
    setup_cpuid_table(cc_info);

    /*
    @@ -2246,16 +2228,14 @@ static struct platform_device sev_guest_device = {
    static int __init snp_init_platform_device(void)
    {
    struct sev_guest_platform_data data;
    - u64 gpa;

    if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
    return -ENODEV;

    - gpa = get_secrets_page();
    - if (!gpa)
    + if (!secrets_pa)
    return -ENODEV;

    - data.secrets_gpa = gpa;
    + data.secrets_gpa = secrets_pa;
    if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
    return -ENODEV;

    --
    2.34.1
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