1 files changed, 375 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
new file mode 100644
index 0000000000..424a5107cd
--- /dev/null
+++ b/arch/arm64/kvm/hyp/exception.c
@@ -0,0 +1,375 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Fault injection for both 32 and 64bit 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 <hyp/adjust_pc.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
+
+#if !defined (__KVM_NVHE_HYPERVISOR__) && !defined (__KVM_VHE_HYPERVISOR__)
+#error Hypervisor code only!
+#endif
+
+static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
+{
+	u64 val;
+
+	if (unlikely(vcpu_has_nv(vcpu)))
+		return vcpu_read_sys_reg(vcpu, reg);
+	else if (__vcpu_read_sys_reg_from_cpu(reg, &val))
+		return val;
+
+	return __vcpu_sys_reg(vcpu, reg);
+}
+
+static inline void __vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
+{
+	if (unlikely(vcpu_has_nv(vcpu)))
+		vcpu_write_sys_reg(vcpu, val, reg);
+	else if (!__vcpu_write_sys_reg_to_cpu(val, reg))
+		__vcpu_sys_reg(vcpu, reg) = val;
+}
+
+static void __vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long target_mode,
+			      u64 val)
+{
+	if (unlikely(vcpu_has_nv(vcpu))) {
+		if (target_mode == PSR_MODE_EL1h)
+			vcpu_write_sys_reg(vcpu, val, SPSR_EL1);
+		else
+			vcpu_write_sys_reg(vcpu, val, SPSR_EL2);
+	} else if (has_vhe()) {
+		write_sysreg_el1(val, SYS_SPSR);
+	} else {
+		__vcpu_sys_reg(vcpu, SPSR_EL1) = val;
+	}
+}
+
+static void __vcpu_write_spsr_abt(struct kvm_vcpu *vcpu, u64 val)
+{
+	if (has_vhe())
+		write_sysreg(val, spsr_abt);
+	else
+		vcpu->arch.ctxt.spsr_abt = val;
+}
+
+static void __vcpu_write_spsr_und(struct kvm_vcpu *vcpu, u64 val)
+{
+	if (has_vhe())
+		write_sysreg(val, spsr_und);
+	else
+		vcpu->arch.ctxt.spsr_und = val;
+}
+
+/*
+ * This performs the exception entry at a given EL (@target_mode), stashing PC
+ * and PSTATE into ELR and SPSR respectively, and compute the new PC/PSTATE.
+ * The EL passed to this function *must* be a non-secure, privileged mode with
+ * bit 0 being set (PSTATE.SP == 1).
+ *
+ * When an exception is taken, most PSTATE fields are left unchanged in the
+ * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all
+ * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx
+ * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0.
+ *
+ * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429.
+ * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426.
+ *
+ * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from
+ * MSB to LSB.
+ */
+static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode,
+			      enum exception_type type)
+{
+	unsigned long sctlr, vbar, old, new, mode;
+	u64 exc_offset;
+
+	mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT);
+
+	if      (mode == target_mode)
+		exc_offset = CURRENT_EL_SP_ELx_VECTOR;
+	else if ((mode | PSR_MODE_THREAD_BIT) == target_mode)
+		exc_offset = CURRENT_EL_SP_EL0_VECTOR;
+	else if (!(mode & PSR_MODE32_BIT))
+		exc_offset = LOWER_EL_AArch64_VECTOR;
+	else
+		exc_offset = LOWER_EL_AArch32_VECTOR;
+
+	switch (target_mode) {
+	case PSR_MODE_EL1h:
+		vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL1);
+		sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1);
+		__vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1);
+		break;
+	case PSR_MODE_EL2h:
+		vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL2);
+		sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL2);
+		__vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL2);
+		break;
+	default:
+		/* Don't do that */
+		BUG();
+	}
+
+	*vcpu_pc(vcpu) = vbar + exc_offset + type;
+
+	old = *vcpu_cpsr(vcpu);
+	new = 0;
+
+	new |= (old & PSR_N_BIT);
+	new |= (old & PSR_Z_BIT);
+	new |= (old & PSR_C_BIT);
+	new |= (old & PSR_V_BIT);
+
+	if (kvm_has_mte(kern_hyp_va(vcpu->kvm)))
+		new |= PSR_TCO_BIT;
+
+	new |= (old & PSR_DIT_BIT);
+
+	// PSTATE.UAO is set to zero upon any exception to AArch64
+	// See ARM DDI 0487E.a, page D5-2579.
+
+	// PSTATE.PAN is unchanged unless SCTLR_ELx.SPAN == 0b0
+	// SCTLR_ELx.SPAN is RES1 when ARMv8.1-PAN is not implemented
+	// See ARM DDI 0487E.a, page D5-2578.
+	new |= (old & PSR_PAN_BIT);
+	if (!(sctlr & SCTLR_EL1_SPAN))
+		new |= PSR_PAN_BIT;
+
+	// PSTATE.SS is set to zero upon any exception to AArch64
+	// See ARM DDI 0487E.a, page D2-2452.
+
+	// PSTATE.IL is set to zero upon any exception to AArch64
+	// See ARM DDI 0487E.a, page D1-2306.
+
+	// PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64
+	// See ARM DDI 0487E.a, page D13-3258
+	if (sctlr & SCTLR_ELx_DSSBS)
+		new |= PSR_SSBS_BIT;
+
+	// PSTATE.BTYPE is set to zero upon any exception to AArch64
+	// See ARM DDI 0487E.a, pages D1-2293 to D1-2294.
+
+	new |= PSR_D_BIT;
+	new |= PSR_A_BIT;
+	new |= PSR_I_BIT;
+	new |= PSR_F_BIT;
+
+	new |= target_mode;
+
+	*vcpu_cpsr(vcpu) = new;
+	__vcpu_write_spsr(vcpu, target_mode, old);
+}
+
+/*
+ * When an exception is taken, most CPSR fields are left unchanged in the
+ * handler. However, some are explicitly overridden (e.g. M[4:0]).
+ *
+ * The SPSR/SPSR_ELx layouts differ, and the below is intended to work with
+ * either format. Note: SPSR.J bit doesn't exist in SPSR_ELx, but this bit was
+ * obsoleted by the ARMv7 virtualization extensions and is RES0.
+ *
+ * For the SPSR layout seen from AArch32, see:
+ * - ARM DDI 0406C.d, page B1-1148
+ * - ARM DDI 0487E.a, page G8-6264
+ *
+ * For the SPSR_ELx layout for AArch32 seen from AArch64, see:
+ * - ARM DDI 0487E.a, page C5-426
+ *
+ * Here we manipulate the fields in order of the AArch32 SPSR_ELx layout, from
+ * MSB to LSB.
+ */
+static unsigned long get_except32_cpsr(struct kvm_vcpu *vcpu, u32 mode)
+{
+	u32 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1);
+	unsigned long old, new;
+
+	old = *vcpu_cpsr(vcpu);
+	new = 0;
+
+	new |= (old & PSR_AA32_N_BIT);
+	new |= (old & PSR_AA32_Z_BIT);
+	new |= (old & PSR_AA32_C_BIT);
+	new |= (old & PSR_AA32_V_BIT);
+	new |= (old & PSR_AA32_Q_BIT);
+
+	// CPSR.IT[7:0] are set to zero upon any exception
+	// See ARM DDI 0487E.a, section G1.12.3
+	// See ARM DDI 0406C.d, section B1.8.3
+
+	new |= (old & PSR_AA32_DIT_BIT);
+
+	// CPSR.SSBS is set to SCTLR.DSSBS upon any exception
+	// See ARM DDI 0487E.a, page G8-6244
+	if (sctlr & BIT(31))
+		new |= PSR_AA32_SSBS_BIT;
+
+	// CPSR.PAN is unchanged unless SCTLR.SPAN == 0b0
+	// SCTLR.SPAN is RES1 when ARMv8.1-PAN is not implemented
+	// See ARM DDI 0487E.a, page G8-6246
+	new |= (old & PSR_AA32_PAN_BIT);
+	if (!(sctlr & BIT(23)))
+		new |= PSR_AA32_PAN_BIT;
+
+	// SS does not exist in AArch32, so ignore
+
+	// CPSR.IL is set to zero upon any exception
+	// See ARM DDI 0487E.a, page G1-5527
+
+	new |= (old & PSR_AA32_GE_MASK);
+
+	// CPSR.IT[7:0] are set to zero upon any exception
+	// See prior comment above
+
+	// CPSR.E is set to SCTLR.EE upon any exception
+	// See ARM DDI 0487E.a, page G8-6245
+	// See ARM DDI 0406C.d, page B4-1701
+	if (sctlr & BIT(25))
+		new |= PSR_AA32_E_BIT;
+
+	// CPSR.A is unchanged upon an exception to Undefined, Supervisor
+	// CPSR.A is set upon an exception to other modes
+	// See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+	// See ARM DDI 0406C.d, page B1-1182
+	new |= (old & PSR_AA32_A_BIT);
+	if (mode != PSR_AA32_MODE_UND && mode != PSR_AA32_MODE_SVC)
+		new |= PSR_AA32_A_BIT;
+
+	// CPSR.I is set upon any exception
+	// See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+	// See ARM DDI 0406C.d, page B1-1182
+	new |= PSR_AA32_I_BIT;
+
+	// CPSR.F is set upon an exception to FIQ
+	// CPSR.F is unchanged upon an exception to other modes
+	// See ARM DDI 0487E.a, pages G1-5515 to G1-5516
+	// See ARM DDI 0406C.d, page B1-1182
+	new |= (old & PSR_AA32_F_BIT);
+	if (mode == PSR_AA32_MODE_FIQ)
+		new |= PSR_AA32_F_BIT;
+
+	// CPSR.T is set to SCTLR.TE upon any exception
+	// See ARM DDI 0487E.a, page G8-5514
+	// See ARM DDI 0406C.d, page B1-1181
+	if (sctlr & BIT(30))
+		new |= PSR_AA32_T_BIT;
+
+	new |= mode;
+
+	return new;
+}
+
+/*
+ * 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 enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
+{
+	unsigned long spsr = *vcpu_cpsr(vcpu);
+	bool is_thumb = (spsr & PSR_AA32_T_BIT);
+	u32 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1);
+	u32 return_address;
+
+	*vcpu_cpsr(vcpu) = get_except32_cpsr(vcpu, mode);
+	return_address   = *vcpu_pc(vcpu);
+	return_address  += return_offsets[vect_offset >> 2][is_thumb];
+
+	/* KVM only enters the ABT and UND modes, so only deal with those */
+	switch(mode) {
+	case PSR_AA32_MODE_ABT:
+		__vcpu_write_spsr_abt(vcpu, host_spsr_to_spsr32(spsr));
+		vcpu_gp_regs(vcpu)->compat_lr_abt = return_address;
+		break;
+
+	case PSR_AA32_MODE_UND:
+		__vcpu_write_spsr_und(vcpu, host_spsr_to_spsr32(spsr));
+		vcpu_gp_regs(vcpu)->compat_lr_und = return_address;
+		break;
+	}
+
+	/* Branch to exception vector */
+	if (sctlr & (1 << 13))
+		vect_offset += 0xffff0000;
+	else /* always have security exceptions */
+		vect_offset += __vcpu_read_sys_reg(vcpu, VBAR_EL1);
+
+	*vcpu_pc(vcpu) = vect_offset;
+}
+
+static void kvm_inject_exception(struct kvm_vcpu *vcpu)
+{
+	if (vcpu_el1_is_32bit(vcpu)) {
+		switch (vcpu_get_flag(vcpu, EXCEPT_MASK)) {
+		case unpack_vcpu_flag(EXCEPT_AA32_UND):
+			enter_exception32(vcpu, PSR_AA32_MODE_UND, 4);
+			break;
+		case unpack_vcpu_flag(EXCEPT_AA32_IABT):
+			enter_exception32(vcpu, PSR_AA32_MODE_ABT, 12);
+			break;
+		case unpack_vcpu_flag(EXCEPT_AA32_DABT):
+			enter_exception32(vcpu, PSR_AA32_MODE_ABT, 16);
+			break;
+		default:
+			/* Err... */
+			break;
+		}
+	} else {
+		switch (vcpu_get_flag(vcpu, EXCEPT_MASK)) {
+		case unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC):
+			enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync);
+			break;
+
+		case unpack_vcpu_flag(EXCEPT_AA64_EL2_SYNC):
+			enter_exception64(vcpu, PSR_MODE_EL2h, except_type_sync);
+			break;
+
+		case unpack_vcpu_flag(EXCEPT_AA64_EL2_IRQ):
+			enter_exception64(vcpu, PSR_MODE_EL2h, except_type_irq);
+			break;
+
+		default:
+			/*
+			 * Only EL1_SYNC and EL2_{SYNC,IRQ} makes
+			 * sense so far. Everything else gets silently
+			 * ignored.
+			 */
+			break;
+		}
+	}
+}
+
+/*
+ * Adjust the guest PC (and potentially exception state) depending on
+ * flags provided by the emulation code.
+ */
+void __kvm_adjust_pc(struct kvm_vcpu *vcpu)
+{
+	if (vcpu_get_flag(vcpu, PENDING_EXCEPTION)) {
+		kvm_inject_exception(vcpu);
+		vcpu_clear_flag(vcpu, PENDING_EXCEPTION);
+		vcpu_clear_flag(vcpu, EXCEPT_MASK);
+	} else if (vcpu_get_flag(vcpu, INCREMENT_PC)) {
+		kvm_skip_instr(vcpu);
+		vcpu_clear_flag(vcpu, INCREMENT_PC);
+	}
+}