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arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line

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As we want to be able to disable VHE at runtime, let's match
"id_aa64mmfr1.vh=" from the command line as an override.
This doesn't have much effect yet as our boot code doesn't look
at the cpufeature, but only at the HW registers.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: David Brazdil <dbrazdil@google.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-15-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Marc Zyngier 2021-02-08 09:57:23 +00:00 committed by Will Deacon
parent 3320030355
commit 361db0fca7
3 changed files with 17 additions and 1 deletions
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2
arch/arm64/include/asm/cpufeature.h
View File

@ -818,6 +818,8 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
return 8;
}
extern struct arm64_ftr_override id_aa64mmfr1_override;
u32 get_kvm_ipa_limit(void);
void dump_cpu_features(void);

5
arch/arm64/kernel/cpufeature.c
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@ -557,6 +557,8 @@ static const struct arm64_ftr_bits ftr_raz[] = {
#define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, &no_override)
struct arm64_ftr_override __ro_after_init id_aa64mmfr1_override;
static const struct __ftr_reg_entry {
u32 sys_id;
struct arm64_ftr_reg *reg;
@ -604,7 +606,8 @@ static const struct __ftr_reg_entry {
/* Op1 = 0, CRn = 0, CRm = 7 */
ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
ARM64_FTR_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1),
ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1,
&id_aa64mmfr1_override),
ARM64_FTR_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2),
/* Op1 = 0, CRn = 1, CRm = 2 */

11
arch/arm64/kernel/idreg-override.c
View File

@ -11,6 +11,7 @@
#include <linux/libfdt.h>
#include <asm/cacheflush.h>
#include <asm/cpufeature.h>
#include <asm/setup.h>
#define FTR_DESC_NAME_LEN 20
@ -25,7 +26,17 @@ struct ftr_set_desc {
} fields[];
};
static const struct ftr_set_desc mmfr1 __initconst = {
.name = "id_aa64mmfr1",
.override = &id_aa64mmfr1_override,
.fields = {
{ "vh", ID_AA64MMFR1_VHE_SHIFT },
{}
},
};
static const struct ftr_set_desc * const regs[] __initconst = {
&mmfr1,
};
static int __init find_field(const char *cmdline,