arm: KVM: Handle async aborts delivered while at HYP

Just like for arm64, we can handle asynchronous aborts being
delivered at HYP while being caused by the guest. We use
the exact same method to catch such an abort, and soldier on.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

2 files changed, 46 insertions, 1 deletions

diff --git a/arch/arm/kvm/hyp/entry.S b/arch/arm/kvm/hyp/entry.S
index 21c238871c9e..60783f3b57cc 100644
--- a/arch/arm/kvm/hyp/entry.S
+++ b/arch/arm/kvm/hyp/entry.S
@@ -18,6 +18,7 @@
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
 
         .arch_extension     virt
 
@@ -63,6 +64,36 @@ ENTRY(__guest_exit)
         ldr     lr, [r0, #4]
 
         mov     r0, r1
+        mrs     r1, SPSR
+        mrs     r2, ELR_hyp
+        mrc     p15, 4, r3, c5, c2, 0   @ HSR
+
+        /*
+         * Force loads and stores to complete before unmasking aborts
+         * and forcing the delivery of the exception. This gives us a
+         * single instruction window, which the handler will try to
+         * match.
+         */
+        dsb     sy
+        cpsie   a
+
+        .global abort_guest_exit_start
+abort_guest_exit_start:
+
+        isb
+
+        .global abort_guest_exit_end
+abort_guest_exit_end:
+
+        /*
+         * If we took an abort, r0[31] will be set, and cmp will set
+         * the N bit in PSTATE.
+         */
+        cmp     r0, #0
+        msrmi   SPSR_cxsf, r1
+        msrmi   ELR_hyp, r2
+        mcrmi   p15, 4, r3, c5, c2, 0   @ HSR
+
         bx      lr
 ENDPROC(__guest_exit)
 
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 78091383a5d9..96beb53934c9 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -81,7 +81,6 @@ __kvm_hyp_vector:
         invalid_vector  hyp_undef       ARM_EXCEPTION_UNDEFINED
         invalid_vector  hyp_svc         ARM_EXCEPTION_SOFTWARE
         invalid_vector  hyp_pabt        ARM_EXCEPTION_PREF_ABORT
-        invalid_vector  hyp_dabt        ARM_EXCEPTION_DATA_ABORT
         invalid_vector  hyp_fiq         ARM_EXCEPTION_FIQ
 
 ENTRY(__hyp_do_panic)
@@ -164,6 +163,21 @@ hyp_irq:
         load_vcpu r0                    @ Load VCPU pointer to r0
         b       __guest_exit
 
+hyp_dabt:
+        push    {r0, r1}
+        mrs     r0, ELR_hyp
+        ldr     r1, =abort_guest_exit_start
+THUMB(  add     r1, r1, #1)
+        cmp     r0, r1
+        ldrne   r1, =abort_guest_exit_end
+THUMB(  addne   r1, r1, #1)
+        cmpne   r0, r1
+        pop     {r0, r1}
+        bne     __hyp_panic
+
+        orr     r0, r0, #(1 << ARM_EXIT_WITH_ABORT_BIT)
+        eret
+
         .ltorg
 
         .popsection