[PATCH v3 16/17] arm64: Allow arm64_sw.hvhe on command line

Marc Zyngier
2023-06-09T16:47:04Z

Add the arm64_sw.hvhe=1 option to force the use of the hVHE mode
in the hypervisor code only.

This enables the hVHE mode of operation when using KVM on VHE
hardware.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kernel/idreg-override.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 8c93b6198bf5..c553d30089e5 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -138,11 +138,22 @@ static const struct ftr_set_desc smfr0 __initconst = {
},
};

+static bool __init hvhe_filter(u64 val)
+{
+ u64 mmfr1 = read_sysreg(id_aa64mmfr1_el1);
+
+ return (val == 1 &&
+ lower_32_bits(__boot_status) == BOOT_CPU_MODE_EL2 &&
+ cpuid_feature_extract_unsigned_field(mmfr1,
+ ID_AA64MMFR1_EL1_VH_SHIFT));
+}
+
static const struct ftr_set_desc sw_features __initconst = {
.name = "arm64_sw",
.override = &arm64_sw_feature_override,
.fields = {
FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL),
+ FIELD("hvhe", ARM64_SW_FEATURE_OVERRIDE_HVHE, hvhe_filter),
{}
},
};
--
2.34.1