KVM: arm/arm64: Move cc/it checks under hyp's Makefile to avoid instrumentation
[ Upstream commit 623e1528d4090bd1abaf93ec46f047dee9a6fb32 ]
KVM has helpers to handle the condition codes of trapped aarch32
instructions. These are marked __hyp_text and used from HYP, but they
aren't built by the 'hyp' Makefile, which has all the runes to avoid ASAN
and KCOV instrumentation.
Move this code to a new hyp/aarch32.c to avoid a hyp-panic when starting
an aarch32 guest on a host built with the ASAN/KCOV debug options.
Fixes: 021234ef3752f ("KVM: arm64: Make kvm_condition_valid32() accessible from EL2")
Fixes: 8cebe750c4d9a ("arm64: KVM: Make kvm_skip_instr32 available to HYP")
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/arch/arm/kvm/hyp/Makefile b/arch/arm/kvm/hyp/Makefile
index d2b5ec9..ba88b1e 100644
--- a/arch/arm/kvm/hyp/Makefile
+++ b/arch/arm/kvm/hyp/Makefile
@@ -11,6 +11,7 @@
obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/vgic-v3-sr.o
obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/timer-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/aarch32.o
obj-$(CONFIG_KVM_ARM_HOST) += tlb.o
obj-$(CONFIG_KVM_ARM_HOST) += cp15-sr.o
diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 2fabc2d..feef06f 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -10,6 +10,7 @@
obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/vgic-v3-sr.o
obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/timer-sr.o
+obj-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/hyp/aarch32.o
obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-cpuif-proxy.o
obj-$(CONFIG_KVM_ARM_HOST) += sysreg-sr.o
diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c
index 5abbe9b..6880236 100644
--- a/virt/kvm/arm/aarch32.c
+++ b/virt/kvm/arm/aarch32.c
@@ -26,127 +26,6 @@
#include <asm/kvm_hyp.h>
/*
- * stolen from arch/arm/kernel/opcodes.c
- *
- * condition code lookup table
- * index into the table is test code: EQ, NE, ... LT, GT, AL, NV
- *
- * bit position in short is condition code: NZCV
- */
-static const unsigned short cc_map[16] = {
- 0xF0F0, /* EQ == Z set */
- 0x0F0F, /* NE */
- 0xCCCC, /* CS == C set */
- 0x3333, /* CC */
- 0xFF00, /* MI == N set */
- 0x00FF, /* PL */
- 0xAAAA, /* VS == V set */
- 0x5555, /* VC */
- 0x0C0C, /* HI == C set && Z clear */
- 0xF3F3, /* LS == C clear || Z set */
- 0xAA55, /* GE == (N==V) */
- 0x55AA, /* LT == (N!=V) */
- 0x0A05, /* GT == (!Z && (N==V)) */
- 0xF5FA, /* LE == (Z || (N!=V)) */
- 0xFFFF, /* AL always */
- 0 /* NV */
-};
-
-/*
- * Check if a trapped instruction should have been executed or not.
- */
-bool __hyp_text kvm_condition_valid32(const struct kvm_vcpu *vcpu)
-{
- unsigned long cpsr;
- u32 cpsr_cond;
- int cond;
-
- /* Top two bits non-zero? Unconditional. */
- if (kvm_vcpu_get_hsr(vcpu) >> 30)
- return true;
-
- /* Is condition field valid? */
- cond = kvm_vcpu_get_condition(vcpu);
- if (cond == 0xE)
- return true;
-
- cpsr = *vcpu_cpsr(vcpu);
-
- if (cond < 0) {
- /* This can happen in Thumb mode: examine IT state. */
- unsigned long it;
-
- it = ((cpsr >> 8) & 0xFC) | ((cpsr >> 25) & 0x3);
-
- /* it == 0 => unconditional. */
- if (it == 0)
- return true;
-
- /* The cond for this insn works out as the top 4 bits. */
- cond = (it >> 4);
- }
-
- cpsr_cond = cpsr >> 28;
-
- if (!((cc_map[cond] >> cpsr_cond) & 1))
- return false;
-
- return true;
-}
-
-/**
- * adjust_itstate - adjust ITSTATE when emulating instructions in IT-block
- * @vcpu: The VCPU pointer
- *
- * When exceptions occur while instructions are executed in Thumb IF-THEN
- * blocks, the ITSTATE field of the CPSR is not advanced (updated), so we have
- * to do this little bit of work manually. The fields map like this:
- *
- * IT[7:0] -> CPSR[26:25],CPSR[15:10]
- */
-static void __hyp_text kvm_adjust_itstate(struct kvm_vcpu *vcpu)
-{
- unsigned long itbits, cond;
- unsigned long cpsr = *vcpu_cpsr(vcpu);
- bool is_arm = !(cpsr & PSR_AA32_T_BIT);
-
- if (is_arm || !(cpsr & PSR_AA32_IT_MASK))
- return;
-
- cond = (cpsr & 0xe000) >> 13;
- itbits = (cpsr & 0x1c00) >> (10 - 2);
- itbits |= (cpsr & (0x3 << 25)) >> 25;
-
- /* Perform ITAdvance (see page A2-52 in ARM DDI 0406C) */
- if ((itbits & 0x7) == 0)
- itbits = cond = 0;
- else
- itbits = (itbits << 1) & 0x1f;
-
- cpsr &= ~PSR_AA32_IT_MASK;
- cpsr |= cond << 13;
- cpsr |= (itbits & 0x1c) << (10 - 2);
- cpsr |= (itbits & 0x3) << 25;
- *vcpu_cpsr(vcpu) = cpsr;
-}
-
-/**
- * kvm_skip_instr - skip a trapped instruction and proceed to the next
- * @vcpu: The vcpu pointer
- */
-void __hyp_text kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr)
-{
- bool is_thumb;
-
- is_thumb = !!(*vcpu_cpsr(vcpu) & PSR_AA32_T_BIT);
- if (is_thumb && !is_wide_instr)
- *vcpu_pc(vcpu) += 2;
- else
- *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] = {
diff --git a/virt/kvm/arm/hyp/aarch32.c b/virt/kvm/arm/hyp/aarch32.c
new file mode 100644
index 0000000..d31f267
--- /dev/null
+++ b/virt/kvm/arm/hyp/aarch32.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hyp portion of the (not much of an) Emulation layer for 32bit guests.
+ *
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * based on arch/arm/kvm/emulate.c
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_hyp.h>
+
+/*
+ * stolen from arch/arm/kernel/opcodes.c
+ *
+ * condition code lookup table
+ * index into the table is test code: EQ, NE, ... LT, GT, AL, NV
+ *
+ * bit position in short is condition code: NZCV
+ */
+static const unsigned short cc_map[16] = {
+ 0xF0F0, /* EQ == Z set */
+ 0x0F0F, /* NE */
+ 0xCCCC, /* CS == C set */
+ 0x3333, /* CC */
+ 0xFF00, /* MI == N set */
+ 0x00FF, /* PL */
+ 0xAAAA, /* VS == V set */
+ 0x5555, /* VC */
+ 0x0C0C, /* HI == C set && Z clear */
+ 0xF3F3, /* LS == C clear || Z set */
+ 0xAA55, /* GE == (N==V) */
+ 0x55AA, /* LT == (N!=V) */
+ 0x0A05, /* GT == (!Z && (N==V)) */
+ 0xF5FA, /* LE == (Z || (N!=V)) */
+ 0xFFFF, /* AL always */
+ 0 /* NV */
+};
+
+/*
+ * Check if a trapped instruction should have been executed or not.
+ */
+bool __hyp_text kvm_condition_valid32(const struct kvm_vcpu *vcpu)
+{
+ unsigned long cpsr;
+ u32 cpsr_cond;
+ int cond;
+
+ /* Top two bits non-zero? Unconditional. */
+ if (kvm_vcpu_get_hsr(vcpu) >> 30)
+ return true;
+
+ /* Is condition field valid? */
+ cond = kvm_vcpu_get_condition(vcpu);
+ if (cond == 0xE)
+ return true;
+
+ cpsr = *vcpu_cpsr(vcpu);
+
+ if (cond < 0) {
+ /* This can happen in Thumb mode: examine IT state. */
+ unsigned long it;
+
+ it = ((cpsr >> 8) & 0xFC) | ((cpsr >> 25) & 0x3);
+
+ /* it == 0 => unconditional. */
+ if (it == 0)
+ return true;
+
+ /* The cond for this insn works out as the top 4 bits. */
+ cond = (it >> 4);
+ }
+
+ cpsr_cond = cpsr >> 28;
+
+ if (!((cc_map[cond] >> cpsr_cond) & 1))
+ return false;
+
+ return true;
+}
+
+/**
+ * adjust_itstate - adjust ITSTATE when emulating instructions in IT-block
+ * @vcpu: The VCPU pointer
+ *
+ * When exceptions occur while instructions are executed in Thumb IF-THEN
+ * blocks, the ITSTATE field of the CPSR is not advanced (updated), so we have
+ * to do this little bit of work manually. The fields map like this:
+ *
+ * IT[7:0] -> CPSR[26:25],CPSR[15:10]
+ */
+static void __hyp_text kvm_adjust_itstate(struct kvm_vcpu *vcpu)
+{
+ unsigned long itbits, cond;
+ unsigned long cpsr = *vcpu_cpsr(vcpu);
+ bool is_arm = !(cpsr & PSR_AA32_T_BIT);
+
+ if (is_arm || !(cpsr & PSR_AA32_IT_MASK))
+ return;
+
+ cond = (cpsr & 0xe000) >> 13;
+ itbits = (cpsr & 0x1c00) >> (10 - 2);
+ itbits |= (cpsr & (0x3 << 25)) >> 25;
+
+ /* Perform ITAdvance (see page A2-52 in ARM DDI 0406C) */
+ if ((itbits & 0x7) == 0)
+ itbits = cond = 0;
+ else
+ itbits = (itbits << 1) & 0x1f;
+
+ cpsr &= ~PSR_AA32_IT_MASK;
+ cpsr |= cond << 13;
+ cpsr |= (itbits & 0x1c) << (10 - 2);
+ cpsr |= (itbits & 0x3) << 25;
+ *vcpu_cpsr(vcpu) = cpsr;
+}
+
+/**
+ * kvm_skip_instr - skip a trapped instruction and proceed to the next
+ * @vcpu: The vcpu pointer
+ */
+void __hyp_text kvm_skip_instr32(struct kvm_vcpu *vcpu, bool is_wide_instr)
+{
+ bool is_thumb;
+
+ is_thumb = !!(*vcpu_cpsr(vcpu) & PSR_AA32_T_BIT);
+ if (is_thumb && !is_wide_instr)
+ *vcpu_pc(vcpu) += 2;
+ else
+ *vcpu_pc(vcpu) += 4;
+ kvm_adjust_itstate(vcpu);
+}