[PATCH 5.15 160/244] KVM: arm64: Treat PMCR_EL1.LC as RES1 on asymmetric systems

Greg Kroah-Hartman
2022-08-23T10:17:52Z

From: Oliver Upton <oliver.upton@linux.dev>

[ Upstream commit f3c6efc72f3b20ec23566e768979802f0a398f04 ]

KVM does not support AArch32 on asymmetric systems. To that end, enforce
AArch64-only behavior on PMCR_EL1.LC when on an asymmetric system.

Fixes: 2122a833316f ("arm64: Allow mismatched 32-bit EL0 support")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220816192554.1455559-2-oliver.upton@linux.dev
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 4 ++++
arch/arm64/kvm/arm.c | 3 +--
arch/arm64/kvm/sys_regs.c | 4 ++--
3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index fc6ee6c5972d..1713630bf8f5 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -795,6 +795,10 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
#define kvm_vcpu_has_pmu(vcpu) \
(test_bit(KVM_ARM_VCPU_PMU_V3, (vcpu)->arch.features))

+#define kvm_supports_32bit_el0() \
+ (system_supports_32bit_el0() && \
+ !static_branch_unlikely(&arm64_mismatched_32bit_el0))
+
int kvm_trng_call(struct kvm_vcpu *vcpu);
#ifdef CONFIG_KVM
extern phys_addr_t hyp_mem_base;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index f181527f9d43..4cb265e15361 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -712,8 +712,7 @@ static bool vcpu_mode_is_bad_32bit(struct kvm_vcpu *vcpu)
if (likely(!vcpu_mode_is_32bit(vcpu)))
return false;

- return !system_supports_32bit_el0() ||
- static_branch_unlikely(&arm64_mismatched_32bit_el0);
+ return !kvm_supports_32bit_el0();
}

/**
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 7c18e429b449..c11612db4a37 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -649,7 +649,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
*/
val = ((pmcr & ~ARMV8_PMU_PMCR_MASK)
| (ARMV8_PMU_PMCR_MASK & 0xdecafbad)) & (~ARMV8_PMU_PMCR_E);
- if (!system_supports_32bit_el0())
+ if (!kvm_supports_32bit_el0())
val |= ARMV8_PMU_PMCR_LC;
__vcpu_sys_reg(vcpu, r->reg) = val;
}
@@ -698,7 +698,7 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
val = __vcpu_sys_reg(vcpu, PMCR_EL0);
val &= ~ARMV8_PMU_PMCR_MASK;
val |= p->regval & ARMV8_PMU_PMCR_MASK;
- if (!system_supports_32bit_el0())
+ if (!kvm_supports_32bit_el0())
val |= ARMV8_PMU_PMCR_LC;
__vcpu_sys_reg(vcpu, PMCR_EL0) = val;
kvm_pmu_handle_pmcr(vcpu, val);
--
2.35.1