diff options
Diffstat (limited to 'arch/arm64/kernel/rsi.c')
| -rw-r--r-- | arch/arm64/kernel/rsi.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c index ce4778141ec7..c64a06f58c0b 100644 --- a/arch/arm64/kernel/rsi.c +++ b/arch/arm64/kernel/rsi.c @@ -84,7 +84,25 @@ static void __init arm64_rsi_setup_memory(void) } } -bool __arm64_is_protected_mmio(phys_addr_t base, size_t size) +/* + * Check if a given PA range is Trusted (e.g., Protected memory, a Trusted Device + * mapping, or an MMIO emulated in the Realm world). + * + * We can rely on the RIPAS value of the region to detect if a given region is + * protected. + * + * RIPAS_DEV - A trusted device memory or a trusted emulated MMIO (in the Realm + * world + * RIPAS_RAM - Memory (RAM), protected by the RMM guarantees. (e.g., Firmware + * reserved regions for data sharing). + * + * RIPAS_DESTROYED is a special case of one of the above, where the host did + * something without our permission and as such we can't do anything about it. + * + * The only case where something is emulated by the untrusted hypervisor or is + * backed by shared memory is indicated by RSI_RIPAS_EMPTY. + */ +bool arm64_rsi_is_protected(phys_addr_t base, size_t size) { enum ripas ripas; phys_addr_t end, top; @@ -101,18 +119,18 @@ bool __arm64_is_protected_mmio(phys_addr_t base, size_t size) break; if (WARN_ON(top <= base)) break; - if (ripas != RSI_RIPAS_DEV) + if (ripas == RSI_RIPAS_EMPTY) break; base = top; } return base >= end; } -EXPORT_SYMBOL(__arm64_is_protected_mmio); +EXPORT_SYMBOL(arm64_rsi_is_protected); static int realm_ioremap_hook(phys_addr_t phys, size_t size, pgprot_t *prot) { - if (__arm64_is_protected_mmio(phys, size)) + if (arm64_rsi_is_protected(phys, size)) *prot = pgprot_encrypted(*prot); else *prot = pgprot_decrypted(*prot); |