Commit f3c6efc7 authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: Treat PMCR_EL1.LC as RES1 on asymmetric systems 



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: 2122a833 ("arm64: Allow mismatched 32-bit EL0 support")
Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220816192554.1455559-2-oliver.upton@linux.dev
parent ae3b1da9

arch/arm64/include/asm/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -929,6 +929,10 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); 
	(system_supports_mte() &&				\

	 test_bit(KVM_ARCH_FLAG_MTE_ENABLED, &(kvm)->arch.flags))



#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;

arch/arm64/kvm/arm.c

+1 −2
Original line number Diff line number Diff line
@@ -757,8 +757,7 @@ 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();

}



/**

arch/arm64/kvm/sys_regs.c

+2 −2
Original line number Diff line number Diff line
@@ -652,7 +652,7 @@ 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;

}
@@ -701,7 +701,7 @@ 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);