From a0888cb3a92fc6faf7af727eaf6d93ed3a2aeb91 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 27 Oct 2020 20:58:52 +0000 Subject: [PATCH] FROMLIST: KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support If a vCPU is caught running 32-bit code on a system with mismatched support at EL0, then we should kill it. Acked-by: Marc Zyngier Signed-off-by: Will Deacon Bug: 178507149 Link: https://lore.kernel.org/linux-arch/20201208132835.6151-4-will@kernel.org/ Signed-off-by: Will Deacon Change-Id: Ica5929e242482be530a87d4e2de9e5554c418561 --- arch/arm64/kvm/arm.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index fe60d25c000e..e392e1e77a1f 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -680,6 +680,15 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu) } } +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); +} + /** * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code * @vcpu: The VCPU pointer @@ -863,7 +872,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) * with the asymmetric AArch32 case), return to userspace with * a fatal error. */ - if (!system_supports_32bit_el0() && vcpu_mode_is_32bit(vcpu)) { + if (vcpu_mode_is_bad_32bit(vcpu)) { /* * As we have caught the guest red-handed, decide that * it isn't fit for purpose anymore by making the vcpu