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    Subject[Part1 PATCH v7 07/17] x86/efi: Access EFI data as encrypted when SEV is active
    Date
    From: Tom Lendacky <thomas.lendacky@amd.com>

    EFI data is encrypted when the kernel is run under SEV. Update the
    page table references to be sure the EFI memory areas are accessed
    encrypted.

    Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
    Reviewed-by: Borislav Petkov <bp@suse.de>
    Tested-by: Borislav Petkov <bp@suse.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Matt Fleming <matt@codeblueprint.co.uk>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: linux-efi@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Cc: x86@kernel.org
    ---
    arch/x86/platform/efi/efi_64.c | 16 +++++++++++++++-
    1 file changed, 15 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
    index 12e83888e5b9..5469c9319f43 100644
    --- a/arch/x86/platform/efi/efi_64.c
    +++ b/arch/x86/platform/efi/efi_64.c
    @@ -32,6 +32,7 @@
    #include <linux/reboot.h>
    #include <linux/slab.h>
    #include <linux/ucs2_string.h>
    +#include <linux/mem_encrypt.h>

    #include <asm/setup.h>
    #include <asm/page.h>
    @@ -369,7 +370,11 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
    * as trim_bios_range() will reserve the first page and isolate it away
    * from memory allocators anyway.
    */
    - if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, _PAGE_RW)) {
    + pf = _PAGE_RW;
    + if (sev_active())
    + pf |= _PAGE_ENC;
    +
    + if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, pf)) {
    pr_err("Failed to create 1:1 mapping for the first page!\n");
    return 1;
    }
    @@ -412,6 +417,9 @@ static void __init __map_region(efi_memory_desc_t *md, u64 va)
    if (!(md->attribute & EFI_MEMORY_WB))
    flags |= _PAGE_PCD;

    + if (sev_active())
    + flags |= _PAGE_ENC;
    +
    pfn = md->phys_addr >> PAGE_SHIFT;
    if (kernel_map_pages_in_pgd(pgd, pfn, va, md->num_pages, flags))
    pr_warn("Error mapping PA 0x%llx -> VA 0x%llx!\n",
    @@ -538,6 +546,9 @@ static int __init efi_update_mem_attr(struct mm_struct *mm, efi_memory_desc_t *m
    if (!(md->attribute & EFI_MEMORY_RO))
    pf |= _PAGE_RW;

    + if (sev_active())
    + pf |= _PAGE_ENC;
    +
    return efi_update_mappings(md, pf);
    }

    @@ -589,6 +600,9 @@ void __init efi_runtime_update_mappings(void)
    (md->type != EFI_RUNTIME_SERVICES_CODE))
    pf |= _PAGE_RW;

    + if (sev_active())
    + pf |= _PAGE_ENC;
    +
    efi_update_mappings(md, pf);
    }
    }
    --
    2.9.5
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