KVM: arm: Make inject_abt32() inject an external abort instead

KVM's inject_abt64() injects an external-abort into an aarch64 guest.
The KVM_CAP_ARM_INJECT_EXT_DABT is intended to do exactly this, but
for an aarch32 guest inject_abt32() injects an implementation-defined
exception, 'Lockdown fault'.

Change this to external abort. For non-LPAE we now get the documented:
| Unhandled fault: external abort on non-linefetch (0x008) at 0x9c800f00
and for LPAE:
| Unhandled fault: synchronous external abort (0x210) 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/20200121123356.203000-3-james.morse@arm.com

diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c
index 2da482ca7067f17eed99b829d5da87e9375326bd..0a356aa91aa1a997ac88d2ec5bae3c7f3e05c9dd 100644 (file)
--- a/virt/kvm/arm/aarch32.c
+++ b/virt/kvm/arm/aarch32.c
@@ -15,6 +15,10 @@
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 
+#define DFSR_FSC_EXTABT_LPAE   0x10
+#define DFSR_FSC_EXTABT_nLPAE  0x08
+#define DFSR_LPAE              BIT(9)
+
 /*
  * Table taken from ARMv8 ARM DDI0487B-B, table G1-10.
  */
@@ -182,10 +186,10 @@ 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) {
-               *fsr = 1 << 9 | 0x34;
+               *fsr = DFSR_LPAE | DFSR_FSC_EXTABT_LPAE;
        } else {
-               /* Surprise! DFSR's FS[4] lives in bit 10 */
-               *fsr = BIT(10) | 0x4; /* 0x14 */
+               /* no need to shuffle FS[4] into DFSR[10] as its 0 */
+               *fsr = DFSR_FSC_EXTABT_nLPAE;
        }
 }