| Message ID | 20240701095505.165383-5-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: Support for running as a guest in Arm CCA | expand |
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@arm.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > Signed-off-by: Steven Price <steven.price@arm.com> > --- > 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? Will
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@arm.com> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> Signed-off-by: Steven Price <steven.price@arm.com> >> --- >> 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
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) #define PTE_MAYBE_NG (arm64_use_ng_mappings ? PTE_NG : 0) #define PMD_MAYBE_NG (arm64_use_ng_mappings ? PMD_SECT_NG : 0) diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c index f01bff9dab04..231c1a3ecdeb 100644 --- a/arch/arm64/kernel/rsi.c +++ b/arch/arm64/kernel/rsi.c @@ -8,6 +8,11 @@ #include <linux/psci.h> #include <asm/rsi.h> +struct realm_config config; + +unsigned long prot_ns_shared; +EXPORT_SYMBOL(prot_ns_shared); + DEFINE_STATIC_KEY_FALSE_RO(rsi_present); EXPORT_SYMBOL(rsi_present); @@ -71,6 +76,9 @@ void __init arm64_rsi_init(void) return; if (!rsi_version_matches()) return; + if (rsi_get_realm_config(&config)) + return; + prot_ns_shared = BIT(config.ipa_bits - 1); static_branch_enable(&rsi_present); }