[PATCH 28/29] arm64: KVM: 32bit guest fault injection

Marc Zyngier
2013-03-05T03:56:15Z

Add fault injection capability for 32bit guests.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/inject_fault.c | 79 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 78 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 80b245f..85a4548 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -1,5 +1,5 @@
/*
- * Fault injection for 64bit guests.
+ * Fault injection for both 32 and 64bit guests.
*
* Copyright (C) 2012 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
@@ -24,6 +24,74 @@
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>

+static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
+{
+ unsigned long cpsr;
+ unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
+ bool is_thumb = (new_spsr_value & COMPAT_PSR_T_BIT);
+ u32 return_offset = (is_thumb) ? 4 : 0;
+ u32 sctlr = vcpu->arch.cp15[c1_SCTLR];
+
+ cpsr = mode | COMPAT_PSR_I_BIT;
+
+ if (sctlr & (1 << 30))
+ cpsr |= COMPAT_PSR_T_BIT;
+ if (sctlr & (1 << 25))
+ cpsr |= COMPAT_PSR_E_BIT;
+
+ *vcpu_cpsr(vcpu) = cpsr;
+
+ /* Note: These now point to the banked copies */
+ *vcpu_spsr(vcpu) = new_spsr_value;
+ *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
+
+ /* Branch to exception vector */
+ if (sctlr & (1 << 13))
+ vect_offset += 0xffff0000;
+ else /* always have security exceptions */
+ vect_offset += vcpu->arch.cp15[c12_VBAR];
+
+ *vcpu_pc(vcpu) = vect_offset;
+}
+
+static void inject_undef32(struct kvm_vcpu *vcpu)
+{
+ prepare_fault32(vcpu, COMPAT_PSR_MODE_UND, 4);
+}
+
+/*
+ * Modelled after TakeDataAbortException() and TakePrefetchAbortException
+ * pseudocode.
+ */
+static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
+ unsigned long addr)
+{
+ u32 vect_offset;
+ u32 *far, *fsr;
+ bool is_lpae;
+
+ if (is_pabt) {
+ vect_offset = 12;
+ far = &vcpu->arch.cp15[c6_IFAR];
+ fsr = &vcpu->arch.cp15[c5_IFSR];
+ } else { /* !iabt */
+ vect_offset = 16;
+ far = &vcpu->arch.cp15[c6_DFAR];
+ fsr = &vcpu->arch.cp15[c5_DFSR];
+ }
+
+ prepare_fault32(vcpu, COMPAT_PSR_MODE_ABT | COMPAT_PSR_A_BIT, vect_offset);
+
+ *far = addr;
+
+ /* Always give debug fault for now - should give guest a clue */
+ is_lpae = (vcpu->arch.cp15[c2_TTBCR] >> 31);
+ if (is_lpae)
+ *fsr = 1 << 9 | 0x22;
+ else
+ *fsr = 2;
+}
+
static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
{
unsigned long cpsr = *vcpu_cpsr(vcpu);
@@ -89,6 +157,9 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
*/
void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
{
+ if (!(vcpu->arch.hcr_el2 & HCR_RW))
+ inject_abt32(vcpu, false, addr);
+
inject_abt64(vcpu, false, addr);
}

@@ -102,6 +173,9 @@ void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
*/
void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
{
+ if (!(vcpu->arch.hcr_el2 & HCR_RW))
+ inject_abt32(vcpu, true, addr);
+
inject_abt64(vcpu, true, addr);
}

@@ -113,5 +187,8 @@ void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
*/
void kvm_inject_undefined(struct kvm_vcpu *vcpu)
{
+ if (!(vcpu->arch.hcr_el2 & HCR_RW))
+ inject_undef32(vcpu);
+
inject_undef64(vcpu);
}
--
1.7.12.4