diff options
| author | Tom Lendacky | 2020-09-07 15:16:12 +0200 |
|---|---|---|
| committer | Borislav Petkov | 2020-09-10 21:48:50 +0200 |
| commit | 39336f4ffb2478ad384075cf4ba7ef2e5db2bbd7 (patch) | |
| tree | a3b7660370d24d993046a07b47364e1a73fa8b1f /arch/x86/platform | |
| parent | 4ca68e023b11e4d5908bf9ee326fab01111d77d5 (diff) | |
x86/efi: Add GHCB mappings when SEV-ES is active
Calling down to EFI runtime services can result in the firmware
performing VMGEXIT calls. The firmware is likely to use the GHCB of the
OS (e.g., for setting EFI variables), so each GHCB in the system needs
to be identity-mapped in the EFI page tables, as unencrypted, to avoid
page faults.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ jroedel@suse.de: Moved GHCB mapping loop to sev-es.c ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-72-joro@8bytes.org
Diffstat (limited to 'arch/x86/platform')
| -rw-r--r-- | arch/x86/platform/efi/efi_64.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 6af4da1149ba..8f5759df7776 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -47,6 +47,7 @@ #include <asm/realmode.h> #include <asm/time.h> #include <asm/pgalloc.h> +#include <asm/sev-es.h> /* * We allocate runtime services regions top-down, starting from -4G, i.e. @@ -230,6 +231,15 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) } /* + * When SEV-ES is active, the GHCB as set by the kernel will be used + * by firmware. Create a 1:1 unencrypted mapping for each GHCB. + */ + if (sev_es_efi_map_ghcbs(pgd)) { + pr_err("Failed to create 1:1 mapping for the GHCBs!\n"); + return 1; + } + + /* * When making calls to the firmware everything needs to be 1:1 * mapped and addressable with 32-bit pointers. Map the kernel * text and allocate a new stack because we can't rely on the |