diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2023-08-07 18:27:19 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-08-07 21:03:53 +0200 |
| commit | 31c77a50992e8dd136feed7b67073bb5f1f978cc (patch) | |
| tree | 17eb4e6a59cd635dba3fb6c74a0aa50d98ed7d03 /drivers/firmware/efi/libstub/x86-stub.c | |
| parent | efi/libstub: Add limit argument to efi_random_alloc() (diff) | |
| download | linux-31c77a50992e8dd136feed7b67073bb5f1f978cc.tar.xz linux-31c77a50992e8dd136feed7b67073bb5f1f978cc.zip | |
x86/efistub: Perform SNP feature test while running in the firmware
Before refactoring the EFI stub boot flow to avoid the legacy bare metal
decompressor, duplicate the SNP feature check in the EFI stub before
handing over to the kernel proper.
The SNP feature check can be performed while running under the EFI boot
services, which means it can force the boot to fail gracefully and
return an error to the bootloader if the loaded kernel does not
implement support for all the features that the hypervisor enabled.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-23-ardb@kernel.org
Diffstat (limited to 'drivers/firmware/efi/libstub/x86-stub.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/x86-stub.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index acb1c65bf8ac..b4685da2b8d5 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -15,6 +15,7 @@ #include <asm/setup.h> #include <asm/desc.h> #include <asm/boot.h> +#include <asm/sev.h> #include "efistub.h" #include "x86-stub.h" @@ -790,6 +791,19 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle) return EFI_SUCCESS; } +static bool have_unsupported_snp_features(void) +{ + u64 unsupported; + + unsupported = snp_get_unsupported_features(sev_get_status()); + if (unsupported) { + efi_err("Unsupported SEV-SNP features detected: 0x%llx\n", + unsupported); + return true; + } + return false; +} + static void __noreturn enter_kernel(unsigned long kernel_addr, struct boot_params *boot_params) { @@ -820,6 +834,9 @@ void __noreturn efi_stub_entry(efi_handle_t handle, if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) efi_exit(handle, EFI_INVALID_PARAMETER); + if (have_unsupported_snp_features()) + efi_exit(handle, EFI_UNSUPPORTED); + if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) { efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID); if (efi_dxe_table && |