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authorJintack Lim <jintack.lim@linaro.org>2023-02-09 20:58:03 +0300
committerOliver Upton <oliver.upton@linux.dev>2023-02-11 12:16:11 +0300
commit675cabc89900732a8a90f19a3c6ed314327a96e0 (patch)
treeaf0c74c5ab86ada3c06b033718a13e653e35a16d /arch/arm64
parent5dc4c995db9eb45f6373a956eb1f69460e69e6d4 (diff)
downloadlinux-675cabc89900732a8a90f19a3c6ed314327a96e0.tar.xz
arm64: Add ARM64_HAS_NESTED_VIRT cpufeature
Add a new ARM64_HAS_NESTED_VIRT feature to indicate that the CPU has the ARMv8.3 nested virtualization capability, together with the 'kvm-arm.mode=nested' command line option. This will be used to support nested virtualization in KVM. Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Jintack Lim <jintack.lim@linaro.org> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com> [maz: moved the command-line option to kvm-arm.mode] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230209175820.1939006-2-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/kvm_host.h5
-rw-r--r--arch/arm64/kernel/cpufeature.c25
-rw-r--r--arch/arm64/kvm/arm.c5
-rw-r--r--arch/arm64/tools/cpucaps1
4 files changed, 36 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 35a159d131b5..8919e971abdf 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -60,9 +60,14 @@
enum kvm_mode {
KVM_MODE_DEFAULT,
KVM_MODE_PROTECTED,
+ KVM_MODE_NV,
KVM_MODE_NONE,
};
+#ifdef CONFIG_KVM
enum kvm_mode kvm_get_mode(void);
+#else
+static inline enum kvm_mode kvm_get_mode(void) { return KVM_MODE_NONE; };
+#endif
DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index a77315b338e6..3fc14ee86239 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1956,6 +1956,20 @@ static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
write_sysreg(read_sysreg(tpidr_el1), tpidr_el2);
}
+static bool has_nested_virt_support(const struct arm64_cpu_capabilities *cap,
+ int scope)
+{
+ if (kvm_get_mode() != KVM_MODE_NV)
+ return false;
+
+ if (!has_cpuid_feature(cap, scope)) {
+ pr_warn("unavailable: %s\n", cap->desc);
+ return false;
+ }
+
+ return true;
+}
+
#ifdef CONFIG_ARM64_PAN
static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused)
{
@@ -2216,6 +2230,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.cpu_enable = cpu_copy_el2regs,
},
{
+ .desc = "Nested Virtualization Support",
+ .capability = ARM64_HAS_NESTED_VIRT,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .matches = has_nested_virt_support,
+ .sys_reg = SYS_ID_AA64MMFR2_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64MMFR2_EL1_NV_SHIFT,
+ .field_width = 4,
+ .min_field_value = ID_AA64MMFR2_EL1_NV_IMP,
+ },
+ {
.capability = ARM64_HAS_32BIT_EL0_DO_NOT_USE,
.type = ARM64_CPUCAP_SYSTEM_FEATURE,
.matches = has_32bit_el0,
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 9c5573bc4614..3fd8f37830f2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -2310,6 +2310,11 @@ static int __init early_kvm_mode_cfg(char *arg)
return 0;
}
+ if (strcmp(arg, "nested") == 0 && !WARN_ON(!is_kernel_in_hyp_mode())) {
+ kvm_mode = KVM_MODE_NV;
+ return 0;
+ }
+
return -EINVAL;
}
early_param("kvm-arm.mode", early_kvm_mode_cfg);
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index dfeb2c51e257..1af77a3657f7 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -31,6 +31,7 @@ HAS_GENERIC_AUTH_IMP_DEF
HAS_IRQ_PRIO_MASKING
HAS_LDAPR
HAS_LSE_ATOMICS
+HAS_NESTED_VIRT
HAS_NO_FPSIMD
HAS_NO_HW_PREFETCH
HAS_PAN