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-rw-r--r--arch/arm/include/asm/kvm_emulate.h5
-rw-r--r--arch/arm64/include/asm/kvm_emulate.h32
-rw-r--r--virt/kvm/arm/aarch32.c6
3 files changed, 40 insertions, 3 deletions
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index c488c629e6c8..08d9805f613b 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -53,6 +53,11 @@ static inline void vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long v)
*__vcpu_spsr(vcpu) = v;
}
+static inline unsigned long host_spsr_to_spsr32(unsigned long spsr)
+{
+ return spsr;
+}
+
static inline unsigned long vcpu_get_reg(struct kvm_vcpu *vcpu,
u8 reg_num)
{
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index f407b6bdad2e..53ea7637b7b2 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -219,6 +219,38 @@ static inline void vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long v)
vcpu_gp_regs(vcpu)->spsr[KVM_SPSR_EL1] = v;
}
+/*
+ * The layout of SPSR for an AArch32 state is different when observed from an
+ * AArch64 SPSR_ELx or an AArch32 SPSR_*. This function generates the AArch32
+ * view given an AArch64 view.
+ *
+ * In ARM DDI 0487E.a see:
+ *
+ * - The AArch64 view (SPSR_EL2) in section C5.2.18, page C5-426
+ * - The AArch32 view (SPSR_abt) in section G8.2.126, page G8-6256
+ * - The AArch32 view (SPSR_und) in section G8.2.132, page G8-6280
+ *
+ * Which show the following differences:
+ *
+ * | Bit | AA64 | AA32 | Notes |
+ * +-----+------+------+-----------------------------|
+ * | 24 | DIT | J | J is RES0 in ARMv8 |
+ * | 21 | SS | DIT | SS doesn't exist in AArch32 |
+ *
+ * ... and all other bits are (currently) common.
+ */
+static inline unsigned long host_spsr_to_spsr32(unsigned long spsr)
+{
+ const unsigned long overlap = BIT(24) | BIT(21);
+ unsigned long dit = !!(spsr & PSR_AA32_DIT_BIT);
+
+ spsr &= ~overlap;
+
+ spsr |= dit << 21;
+
+ return spsr;
+}
+
static inline bool vcpu_mode_priv(const struct kvm_vcpu *vcpu)
{
u32 mode;
diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c
index 773cf1439081..631d397ac81b 100644
--- a/virt/kvm/arm/aarch32.c
+++ b/virt/kvm/arm/aarch32.c
@@ -129,15 +129,15 @@ static unsigned long get_except32_cpsr(struct kvm_vcpu *vcpu, u32 mode)
static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
{
- unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
- bool is_thumb = (new_spsr_value & PSR_AA32_T_BIT);
+ unsigned long spsr = *vcpu_cpsr(vcpu);
+ bool is_thumb = (spsr & PSR_AA32_T_BIT);
u32 return_offset = return_offsets[vect_offset >> 2][is_thumb];
u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
*vcpu_cpsr(vcpu) = get_except32_cpsr(vcpu, mode);
/* Note: These now point to the banked copies */
- vcpu_write_spsr(vcpu, new_spsr_value);
+ vcpu_write_spsr(vcpu, host_spsr_to_spsr32(spsr));
*vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
/* Branch to exception vector */