diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2022-02-09 12:10:12 -0600 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 13:22:54 +0200 |
| commit | 5e5ccff60a2977142d39b987a8b90e422d9fc634 (patch) | |
| tree | 66da624e3fa78590b1b7555e8b3a4ec744f0fc5b /arch/x86/include/asm/sev.h | |
| parent | 95d33bfaa3e169cfec1926e0d0f0c6b0ea75d763 (diff) | |
| download | lwn-5e5ccff60a2977142d39b987a8b90e422d9fc634.tar.gz lwn-5e5ccff60a2977142d39b987a8b90e422d9fc634.zip | |
x86/sev: Add helper for validating pages in early enc attribute changes
early_set_memory_{encrypted,decrypted}() are used for changing the page
state from decrypted (shared) to encrypted (private) and vice versa.
When SEV-SNP is active, the page state transition needs to go through
additional steps.
If the page is transitioned from shared to private, then perform the
following after the encryption attribute is set in the page table:
1. Issue the page state change VMGEXIT to add the page as a private
in the RMP table.
2. Validate the page after its successfully added in the RMP table.
To maintain the security guarantees, if the page is transitioned from
private to shared, then perform the following before clearing the
encryption attribute from the page table.
1. Invalidate the page.
2. Issue the page state change VMGEXIT to make the page shared in the
RMP table.
early_set_memory_{encrypted,decrypted}() can be called before the GHCB
is setup so use the SNP page state MSR protocol VMGEXIT defined in the
GHCB specification to request the page state change in the RMP table.
While at it, add a helper snp_prep_memory() which will be used in
probe_roms(), in a later patch.
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-19-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/include/asm/sev.h')
| -rw-r--r-- | arch/x86/include/asm/sev.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 48df02713ee0..f65d257e3d4a 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -123,6 +123,11 @@ static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) return rc; } void setup_ghcb(void); +void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, + unsigned int npages); +void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, + unsigned int npages); +void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -132,6 +137,11 @@ 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; } static inline void setup_ghcb(void) { } +static inline void __init +early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned int npages) { } +static inline void __init +early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned int npages) { } +static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { } #endif #endif |