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authorMarc Zyngier <marc.zyngier@arm.com>2017-10-29 02:18:09 +0000
committerChristoffer Dall <christoffer.dall@linaro.org>2017-11-06 16:23:20 +0100
commit74a64a981662ab34289b3c90f6f964aa38ec1d9f (patch)
tree2b50e644fc682bade8e028ef495e54da5c683668 /virt
parent3eb4271b4ab6d38a3c113a19f358f606702e08ef (diff)
downloadop-kernel-dev-74a64a981662ab34289b3c90f6f964aa38ec1d9f.zip
op-kernel-dev-74a64a981662ab34289b3c90f6f964aa38ec1d9f.tar.gz
KVM: arm/arm64: Unify 32bit fault injection
Both arm and arm64 implementations are capable of injecting faults, and yet have completely divergent implementations, leading to different bugs and reduced maintainability. Let's elect the arm64 version as the canonical one and move it into aarch32.c, which is common to both architectures. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/arm/aarch32.c97
1 files changed, 92 insertions, 5 deletions
diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c
index 79c7c35..8bc479f 100644
--- a/virt/kvm/arm/aarch32.c
+++ b/virt/kvm/arm/aarch32.c
@@ -25,11 +25,6 @@
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
-#ifndef CONFIG_ARM64
-#define COMPAT_PSR_T_BIT PSR_T_BIT
-#define COMPAT_PSR_IT_MASK PSR_IT_MASK
-#endif
-
/*
* stolen from arch/arm/kernel/opcodes.c
*
@@ -150,3 +145,95 @@ void __hyp_text kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr)
*vcpu_pc(vcpu) += 4;
kvm_adjust_itstate(vcpu);
}
+
+/*
+ * Table taken from ARMv8 ARM DDI0487B-B, table G1-10.
+ */
+static const u8 return_offsets[8][2] = {
+ [0] = { 0, 0 }, /* Reset, unused */
+ [1] = { 4, 2 }, /* Undefined */
+ [2] = { 0, 0 }, /* SVC, unused */
+ [3] = { 4, 4 }, /* Prefetch abort */
+ [4] = { 8, 8 }, /* Data abort */
+ [5] = { 0, 0 }, /* HVC, unused */
+ [6] = { 4, 4 }, /* IRQ, unused */
+ [7] = { 4, 4 }, /* FIQ, unused */
+};
+
+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 = return_offsets[vect_offset >> 2][is_thumb];
+ u32 sctlr = vcpu_cp15(vcpu, 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_reg32(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_cp15(vcpu, c12_VBAR);
+
+ *vcpu_pc(vcpu) = vect_offset;
+}
+
+void kvm_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_cp15(vcpu, c6_IFAR);
+ fsr = &vcpu_cp15(vcpu, c5_IFSR);
+ } else { /* !iabt */
+ vect_offset = 16;
+ far = &vcpu_cp15(vcpu, c6_DFAR);
+ fsr = &vcpu_cp15(vcpu, c5_DFSR);
+ }
+
+ prepare_fault32(vcpu, COMPAT_PSR_MODE_ABT | COMPAT_PSR_A_BIT, vect_offset);
+
+ *far = addr;
+
+ /* Give the guest an IMPLEMENTATION DEFINED exception */
+ is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
+ if (is_lpae)
+ *fsr = 1 << 9 | 0x34;
+ else
+ *fsr = 0x14;
+}
+
+void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+ inject_abt32(vcpu, false, addr);
+}
+
+void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr)
+{
+ inject_abt32(vcpu, true, addr);
+}
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