On 09/07/2024 11:53, Will Deacon wrote: > On Mon, Jul 01, 2024 at 10:54:54AM +0100, Steven Price wrote: >> The top bit of the configured IPA size is used as an attribute to >> control whether the address is protected or shared. Query the >> configuration from the RMM to assertain which bit this is. >> >> Co-developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> >> Signed-off-by: Steven Price <steven.price@xxxxxxx> >> --- >> Changes since v2: >> * Drop unneeded extra brackets from PROT_NS_SHARED. >> * Drop the explicit alignment from 'config' as struct realm_config now >> specifies the alignment. >> --- >> arch/arm64/include/asm/pgtable-prot.h | 3 +++ >> arch/arm64/kernel/rsi.c | 8 ++++++++ >> 2 files changed, 11 insertions(+) >> >> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h >> index b11cfb9fdd37..6c29f3b32eba 100644 >> --- a/arch/arm64/include/asm/pgtable-prot.h >> +++ b/arch/arm64/include/asm/pgtable-prot.h >> @@ -70,6 +70,9 @@ >> #include <asm/pgtable-types.h> >> >> extern bool arm64_use_ng_mappings; >> +extern unsigned long prot_ns_shared; >> + >> +#define PROT_NS_SHARED (prot_ns_shared) > > Since the _vast_ majority of Linux systems won't be running in a realm, > can we use a static key to avoid loading a constant each time? Fair enough, the following should do the trick: #define PROT_NS_SHARED (is_realm_world() ? prot_ns_shared : 0) Thanks, Steve
