Messages in this thread | | | Subject | Re: [RFC Part1 PATCH v3 08/17] x86/efi: Access EFI data as encrypted when SEV is active | From | Tom Lendacky <> | Date | Thu, 17 Aug 2017 13:42:04 -0500 |
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On 7/28/2017 5:31 AM, Borislav Petkov wrote: > On Mon, Jul 24, 2017 at 02:07:48PM -0500, Brijesh Singh wrote: >> 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> >> --- >> arch/x86/platform/efi/efi_64.c | 15 ++++++++++++++- >> 1 file changed, 14 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c >> index 12e8388..1ecb3f6 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 +370,10 @@ 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; > > \n here > >> + 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 +416,9 @@ 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", >> @@ -511,6 +518,9 @@ static int __init efi_update_mappings(efi_memory_desc_t *md, unsigned long pf) >> pgd_t *pgd = efi_pgd; >> int err1, err2; >> >> + if (sev_active()) >> + pf |= _PAGE_ENC; > > Move this assignment to the caller efi_update_mem_attr() where pf is being > set...
Will do.
> >> + >> /* Update the 1:1 mapping */ >> pfn = md->phys_addr >> PAGE_SHIFT; >> err1 = kernel_map_pages_in_pgd(pgd, pfn, md->phys_addr, md->num_pages, pf); >> @@ -589,6 +599,9 @@ void __init efi_runtime_update_mappings(void) >> (md->type != EFI_RUNTIME_SERVICES_CODE)) >> pf |= _PAGE_RW; >> >> + if (sev_active()) >> + pf |= _PAGE_ENC; > > ... just like here.
Yup.
Thanks, Tom
> >> + >> efi_update_mappings(md, pf); > > In general, I'm not totally excited about that sprinkling of if > (sev_active())... :-\ >
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