[PATCH v3 05/23] arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature

Marc Zyngier
2016-02-03T17:59:58Z

Add a new ARM64_HAS_VIRT_HOST_EXTN features to indicate that the
CPU has the ARMv8.1 VHE capability.

This will be used to trigger kernel patching in KVM.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/cpufeature.h | 3 ++-
arch/arm64/kernel/cpufeature.c | 11 +++++++++++
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 8f271b8..c705d6a 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -30,8 +30,9 @@
#define ARM64_HAS_LSE_ATOMICS 5
#define ARM64_WORKAROUND_CAVIUM_23154 6
#define ARM64_WORKAROUND_834220 7
+#define ARM64_HAS_VIRT_HOST_EXTN 8

-#define ARM64_NCAPS 8
+#define ARM64_NCAPS 9

#ifndef __ASSEMBLY__

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 5c90aa4..ba74519 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -26,6 +26,7 @@
#include <asm/cpu_ops.h>
#include <asm/processor.h>
#include <asm/sysreg.h>
+#include <asm/virt.h>

unsigned long elf_hwcap __read_mostly;
EXPORT_SYMBOL_GPL(elf_hwcap);
@@ -621,6 +622,11 @@ static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry)
return has_sre;
}

+static bool runs_at_el2(const struct arm64_cpu_capabilities *entry)
+{
+ return is_kernel_in_hyp_mode();
+}
+
static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "GIC system register CPU interface",
@@ -651,6 +657,11 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.min_field_value = 2,
},
#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+ {
+ .desc = "Virtualization Host Extensions",
+ .capability = ARM64_HAS_VIRT_HOST_EXTN,
+ .matches = runs_at_el2,
+ },
{},
};

--
2.1.4