ARM: KVM: don't special case PC when doing an MMIO

Admitedly, reading a MMIO register to load PC is very weird.
Writing PC to a MMIO register is probably even worse. But
the architecture doesn't forbid any of these, and injecting
a Prefetch Abort is the wrong thing to do anyway.

Remove this check altogether, and let the adventurous guest
wander into LaLaLand if they feel compelled to do so.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>

2 files changed, 0 insertions, 11 deletions

diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 82b4babead2c..a464e8d7b6c5 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -65,11 +65,6 @@ static inline bool vcpu_mode_priv(struct kvm_vcpu *vcpu)
         return cpsr_mode > USR_MODE;;
 }
 
-static inline bool kvm_vcpu_reg_is_pc(struct kvm_vcpu *vcpu, int reg)
-{
-        return reg == 15;
-}
-
 static inline u32 kvm_vcpu_get_hsr(struct kvm_vcpu *vcpu)
 {
         return vcpu->arch.fault.hsr;
diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
index 72a12f2171b2..b8e06b7a2833 100644
--- a/arch/arm/kvm/mmio.c
+++ b/arch/arm/kvm/mmio.c
@@ -86,12 +86,6 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
         sign_extend = kvm_vcpu_dabt_issext(vcpu);
         rt = kvm_vcpu_dabt_get_rd(vcpu);
 
-        if (kvm_vcpu_reg_is_pc(vcpu, rt)) {
-                /* IO memory trying to read/write pc */
-                kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
-                return 1;
-        }
-
         mmio->is_write = is_write;
         mmio->phys_addr = fault_ipa;
         mmio->len = len;