| From 3ae112e9b81b5e87d7122c55e7d161cac3270de0 Mon Sep 17 00:00:00 2001 |
| From: James Morse <james.morse@arm.com> |
| Date: Tue, 21 Jan 2020 12:33:55 +0000 |
| Subject: [PATCH] KVM: arm: Fix DFSR setting for non-LPAE aarch32 guests |
| |
| commit 018f22f95e8a6c3e27188b7317ef2c70a34cb2cd upstream. |
| |
| Beata reports that KVM_SET_VCPU_EVENTS doesn't inject the expected |
| exception to a non-LPAE aarch32 guest. |
| |
| The host intends to inject DFSR.FS=0x14 "IMPLEMENTATION DEFINED fault |
| (Lockdown fault)", but the guest receives DFSR.FS=0x04 "Fault on |
| instruction cache maintenance". This fault is hooked by |
| do_translation_fault() since ARMv6, which goes on to silently 'handle' |
| the exception, and restart the faulting instruction. |
| |
| It turns out, when TTBCR.EAE is clear DFSR is split, and FS[4] has |
| to shuffle up to DFSR[10]. |
| |
| As KVM only does this in one place, fix up the static values. We |
| now get the expected: |
| | Unhandled fault: lock abort (0x404) at 0x9c800f00 |
| |
| Fixes: 74a64a981662a ("KVM: arm/arm64: Unify 32bit fault injection") |
| Reported-by: Beata Michalska <beata.michalska@linaro.org> |
| Signed-off-by: James Morse <james.morse@arm.com> |
| Signed-off-by: Marc Zyngier <maz@kernel.org> |
| Link: https://lore.kernel.org/r/20200121123356.203000-2-james.morse@arm.com |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c |
| index 631d397ac81b..2da482ca7067 100644 |
| --- a/virt/kvm/arm/aarch32.c |
| +++ b/virt/kvm/arm/aarch32.c |
| @@ -181,10 +181,12 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, |
| |
| /* Give the guest an IMPLEMENTATION DEFINED exception */ |
| is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31); |
| - if (is_lpae) |
| + if (is_lpae) { |
| *fsr = 1 << 9 | 0x34; |
| - else |
| - *fsr = 0x14; |
| + } else { |
| + /* Surprise! DFSR's FS[4] lives in bit 10 */ |
| + *fsr = BIT(10) | 0x4; /* 0x14 */ |
| + } |
| } |
| |
| void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr) |
| -- |
| 2.7.4 |
| |
