Expose the boolean value whether the system is running with KVM in
protected mode (nVHE + kernel param). CPU capability was selected over
a global variable to allow use in alternatives.
Signed-off-by: David Brazdil <dbrazdil@xxxxxxxxxx>
---
arch/arm64/include/asm/cpucaps.h | 3 ++-
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/virt.h | 8 ++++++++
arch/arm64/kernel/cpufeature.c | 22 ++++++++++++++++++++++
arch/arm64/kvm/arm.c | 9 ++++++++-
5 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 162539d4c8cd..42f850718d4b 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -66,7 +66,8 @@
#define ARM64_HAS_TLB_RANGE 56
#define ARM64_MTE 57
#define ARM64_WORKAROUND_1508412 58
+#define ARM64_KVM_PROTECTED_MODE 59
-#define ARM64_NCAPS 59
+#define ARM64_NCAPS 60
#endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index bca38ccade58..11beda85ee7e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -58,6 +58,7 @@ enum kvm_mode {
KVM_MODE_DEFAULT,
KVM_MODE_PROTECTED,
};
+enum kvm_mode kvm_get_mode(void);
DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 6069be50baf9..eb81dcc220b6 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -97,6 +97,14 @@ static __always_inline bool has_vhe(void)
return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
}
+static __always_inline bool is_protected_kvm_enabled(void)
+{
+ if (is_vhe_hyp_code())
+ return false;
+ else
+ return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
+}
+
#endif /* __ASSEMBLY__ */
#endif /* ! __ASM__VIRT_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 280b10762f6b..5f9e557fa1f7 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -74,6 +74,7 @@
#include <asm/cpufeature.h>
#include <asm/cpu_ops.h>
#include <asm/fpsimd.h>
+#include <asm/kvm_host.h>
#include <asm/mmu_context.h>
#include <asm/mte.h>
#include <asm/processor.h>
@@ -1709,6 +1710,21 @@ static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap)
}
#endif /* CONFIG_ARM64_MTE */
+#ifdef CONFIG_KVM
+static bool is_kvm_protected_mode(const struct arm64_cpu_capabilities *entry, int __unused)
+{
+ if (kvm_get_mode() != KVM_MODE_PROTECTED)
+ return false;
+
+ if (is_kernel_in_hyp_mode()) {
+ pr_warn("Protected KVM not available with VHE\n");
+ return false;
+ }
+
+ return true;
+}
+#endif /* CONFIG_KVM */
+
/* Internal helper functions to match cpu capability type */
static bool
cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap)
@@ -1822,6 +1838,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.field_pos = ID_AA64PFR0_EL1_SHIFT,
.min_field_value = ID_AA64PFR0_EL1_32BIT_64BIT,
},
+ {
+ .desc = "Protected KVM",
+ .capability = ARM64_KVM_PROTECTED_MODE,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .matches = is_kvm_protected_mode,
+ },
#endif
{
.desc = "Kernel page table isolation (KPTI)",
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 01cf6ac5b2cb..d9e8d7dc7e11 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1849,7 +1849,9 @@ int kvm_arch_init(void *opaque)
if (err)
goto out_hyp;
- if (in_hyp_mode)
+ if (is_protected_kvm_enabled())
+ kvm_info("Protected nVHE mode initialized successfully\n");
+ else if (in_hyp_mode)
kvm_info("VHE mode initialized successfully\n");
else
kvm_info("Hyp mode initialized successfully\n");
@@ -1884,6 +1886,11 @@ static int __init early_kvm_mode_cfg(char *arg)
}
early_param("kvm-arm.mode", early_kvm_mode_cfg);
+enum kvm_mode kvm_get_mode(void)
+{
+ return kvm_mode;
+}
+
static int arm_init(void)
{
int rc = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
--
2.29.2.454.gaff20da3a2-goog
