diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2022-02-09 12:10:08 -0600 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 13:10:34 +0200 |
| commit | 81cc3df9a90e7817494421ecc48ede6bd5e8132b (patch) | |
| tree | fd88593d7c636ce70ec6fe5dff2cc40294238e71 /arch/x86/include/asm/sev.h | |
| parent | 0bd6f1e526070271dbe0f626b123b4f6b01dc79c (diff) | |
| download | lwn-81cc3df9a90e7817494421ecc48ede6bd5e8132b.tar.gz lwn-81cc3df9a90e7817494421ecc48ede6bd5e8132b.zip | |
x86/sev: Check the VMPL level
The Virtual Machine Privilege Level (VMPL) feature in the SEV-SNP
architecture allows a guest VM to divide its address space into four
levels. The level can be used to provide hardware isolated abstraction
layers within a VM. VMPL0 is the highest privilege level, and VMPL3 is
the least privilege level. Certain operations must be done by the VMPL0
software, such as:
* Validate or invalidate memory range (PVALIDATE instruction)
* Allocate VMSA page (RMPADJUST instruction when VMSA=1)
The initial SNP support requires that the guest kernel is running at
VMPL0. Add such a check to verify the guest is running at level 0 before
continuing the boot. There is no easy method to query the current VMPL
level, so use the RMPADJUST instruction to determine whether the guest
is running at the VMPL0.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-15-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/include/asm/sev.h')
| -rw-r--r-- | arch/x86/include/asm/sev.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 4ee98976aed8..e37451849165 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -63,6 +63,9 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); /* Software defined (when rFlags.CF = 1) */ #define PVALIDATE_FAIL_NOUPDATE 255 +/* RMP page size */ +#define RMP_PG_SIZE_4K 0 + #ifdef CONFIG_AMD_MEM_ENCRYPT extern struct static_key_false sev_es_enable_key; extern void __sev_es_ist_enter(struct pt_regs *regs); @@ -90,6 +93,18 @@ extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, struct es_em_ctxt *ctxt, u64 exit_code, u64 exit_info_1, u64 exit_info_2); +static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) +{ + int rc; + + /* "rmpadjust" mnemonic support in binutils 2.36 and newer */ + asm volatile(".byte 0xF3,0x0F,0x01,0xFE\n\t" + : "=a"(rc) + : "a"(vaddr), "c"(rmp_psize), "d"(attrs) + : "memory", "cc"); + + return rc; +} static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { bool no_rmpupdate; @@ -114,6 +129,7 @@ static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { ret static inline void sev_es_nmi_complete(void) { } static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; } static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; } +static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { return 0; } #endif #endif |