KVM: arm64: Rewrite system register accessors to read/write functions

Currently we access the system registers array via the vcpu_sys_reg()
macro.  However, we are about to change the behavior to some times
modify the register file directly, so let's change this to two
primitives:

 * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg()
 * Direct array access macro __vcpu_sys_reg()

The accessor macros should be used in places where the code needs to
access the currently loaded VCPU's state as observed by the guest.  For
example, when trapping on cache related registers, a write to a system
register should go directly to the VCPU version of the register.

The direct array access macro can be used in places where the VCPU is
known to never be running (for example userspace access) or for
registers which are never context switched (for example all the PMU
system registers).

This rewrites all users of vcpu_sys_regs to one of the macros described
above.

No functional change.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

5 files changed, 62 insertions, 51 deletions

diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index feedb877cff8..a1f4ebdfe6d3 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -46,7 +46,9 @@ static DEFINE_PER_CPU(u32, mdcr_el2);
  */
 static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
 {
-	vcpu->arch.guest_debug_preserved.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
+	u64 val = vcpu_read_sys_reg(vcpu, MDSCR_EL1);
+
+	vcpu->arch.guest_debug_preserved.mdscr_el1 = val;
 
 	trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
 				vcpu->arch.guest_debug_preserved.mdscr_el1);
@@ -54,10 +56,12 @@ static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
 
 static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
 {
-	vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_preserved.mdscr_el1;
+	u64 val = vcpu->arch.guest_debug_preserved.mdscr_el1;
+
+	vcpu_write_sys_reg(vcpu, val, MDSCR_EL1);
 
 	trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
-				vcpu_sys_reg(vcpu, MDSCR_EL1));
+				vcpu_read_sys_reg(vcpu, MDSCR_EL1));
 }
 
 /**
@@ -108,6 +112,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
 void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 {
 	bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);
+	unsigned long mdscr;
 
 	trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
 
@@ -152,9 +157,13 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 		 */
 		if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
 			*vcpu_cpsr(vcpu) |=  DBG_SPSR_SS;
-			vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_SS;
+			mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1);
+			mdscr |= DBG_MDSCR_SS;
+			vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1);
 		} else {
-			vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS;
+			mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1);
+			mdscr &= ~DBG_MDSCR_SS;
+			vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1);
 		}
 
 		trace_kvm_arm_set_dreg32("SPSR_EL2", *vcpu_cpsr(vcpu));
@@ -170,7 +179,9 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 		 */
 		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
 			/* Enable breakpoints/watchpoints */
-			vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_MDE;
+			mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1);
+			mdscr |= DBG_MDSCR_MDE;
+			vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1);
 
 			vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
 			vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
@@ -194,12 +205,11 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 		vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
 
 	/* If KDE or MDE are set, perform a full save/restore cycle. */
-	if ((vcpu_sys_reg(vcpu, MDSCR_EL1) & DBG_MDSCR_KDE) ||
-	    (vcpu_sys_reg(vcpu, MDSCR_EL1) & DBG_MDSCR_MDE))
+	if (vcpu_read_sys_reg(vcpu, MDSCR_EL1) & (DBG_MDSCR_KDE | DBG_MDSCR_MDE))
 		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 
 	trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
-	trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
+	trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_read_sys_reg(vcpu, MDSCR_EL1));
 }
 
 void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index 30a3f58cdb7b..63dba401fc7d 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -58,7 +58,7 @@ static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
 		exc_offset = LOWER_EL_AArch32_VECTOR;
 	}
 
-	return vcpu_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
+	return vcpu_read_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
 }
 
 static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
@@ -73,7 +73,7 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
 	*vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
 	*vcpu_spsr(vcpu) = cpsr;
 
-	vcpu_sys_reg(vcpu, FAR_EL1) = addr;
+	vcpu_write_sys_reg(vcpu, addr, FAR_EL1);
 
 	/*
 	 * Build an {i,d}abort, depending on the level and the
@@ -94,7 +94,7 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
 	if (!is_iabt)
 		esr |= ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT;
 
-	vcpu_sys_reg(vcpu, ESR_EL1) = esr | ESR_ELx_FSC_EXTABT;
+	vcpu_write_sys_reg(vcpu, esr | ESR_ELx_FSC_EXTABT, ESR_EL1);
 }
 
 static void inject_undef64(struct kvm_vcpu *vcpu)
@@ -115,7 +115,7 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
 	if (kvm_vcpu_trap_il_is32bit(vcpu))
 		esr |= ESR_ELx_IL;
 
-	vcpu_sys_reg(vcpu, ESR_EL1) = esr;
+	vcpu_write_sys_reg(vcpu, esr, ESR_EL1);
 }
 
 /**
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 691f81c31018..7514db002430 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -133,14 +133,14 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
 	if (!p->is_aarch32 || !p->is_32bit) {
 		val = p->regval;
 	} else {
-		val = vcpu_sys_reg(vcpu, reg);
+		val = vcpu_read_sys_reg(vcpu, reg);
 		if (r->reg % 2)
 			val = (p->regval << 32) | (u64)lower_32_bits(val);
 		else
 			val = ((u64)upper_32_bits(val) << 32) |
 				lower_32_bits(p->regval);
 	}
-	vcpu_sys_reg(vcpu, reg) = val;
+	vcpu_write_sys_reg(vcpu, val, reg);
 
 	kvm_toggle_cache(vcpu, was_enabled);
 	return true;
@@ -249,10 +249,10 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
 			    const struct sys_reg_desc *r)
 {
 	if (p->is_write) {
-		vcpu_sys_reg(vcpu, r->reg) = p->regval;
+		vcpu_write_sys_reg(vcpu, p->regval, r->reg);
 		vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, r->reg);
+		p->regval = vcpu_read_sys_reg(vcpu, r->reg);
 	}
 
 	trace_trap_reg(__func__, r->reg, p->is_write, p->regval);
@@ -465,7 +465,8 @@ static void reset_wcr(struct kvm_vcpu *vcpu,
 
 static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
-	vcpu_sys_reg(vcpu, AMAIR_EL1) = read_sysreg(amair_el1);
+	u64 amair = read_sysreg(amair_el1);
+	vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
 }
 
 static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
@@ -482,7 +483,7 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
 	mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
 	mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
-	vcpu_sys_reg(vcpu, MPIDR_EL1) = (1ULL << 31) | mpidr;
+	vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
 }
 
 static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
@@ -496,12 +497,12 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	 */
 	val = ((pmcr & ~ARMV8_PMU_PMCR_MASK)
 	       | (ARMV8_PMU_PMCR_MASK & 0xdecafbad)) & (~ARMV8_PMU_PMCR_E);
-	vcpu_sys_reg(vcpu, PMCR_EL0) = val;
+	__vcpu_sys_reg(vcpu, PMCR_EL0) = val;
 }
 
 static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags)
 {
-	u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	u64 reg = __vcpu_sys_reg(vcpu, PMUSERENR_EL0);
 	bool enabled = (reg & flags) || vcpu_mode_priv(vcpu);
 
 	if (!enabled)
@@ -543,14 +544,14 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 
 	if (p->is_write) {
 		/* Only update writeable bits of PMCR */
-		val = vcpu_sys_reg(vcpu, PMCR_EL0);
+		val = __vcpu_sys_reg(vcpu, PMCR_EL0);
 		val &= ~ARMV8_PMU_PMCR_MASK;
 		val |= p->regval & ARMV8_PMU_PMCR_MASK;
-		vcpu_sys_reg(vcpu, PMCR_EL0) = val;
+		__vcpu_sys_reg(vcpu, PMCR_EL0) = val;
 		kvm_pmu_handle_pmcr(vcpu, val);
 	} else {
 		/* PMCR.P & PMCR.C are RAZ */
-		val = vcpu_sys_reg(vcpu, PMCR_EL0)
+		val = __vcpu_sys_reg(vcpu, PMCR_EL0)
 		      & ~(ARMV8_PMU_PMCR_P | ARMV8_PMU_PMCR_C);
 		p->regval = val;
 	}
@@ -568,10 +569,10 @@ static bool access_pmselr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		return false;
 
 	if (p->is_write)
-		vcpu_sys_reg(vcpu, PMSELR_EL0) = p->regval;
+		__vcpu_sys_reg(vcpu, PMSELR_EL0) = p->regval;
 	else
 		/* return PMSELR.SEL field */
-		p->regval = vcpu_sys_reg(vcpu, PMSELR_EL0)
+		p->regval = __vcpu_sys_reg(vcpu, PMSELR_EL0)
 			    & ARMV8_PMU_COUNTER_MASK;
 
 	return true;
@@ -604,7 +605,7 @@ static bool pmu_counter_idx_valid(struct kvm_vcpu *vcpu, u64 idx)
 {
 	u64 pmcr, val;
 
-	pmcr = vcpu_sys_reg(vcpu, PMCR_EL0);
+	pmcr = __vcpu_sys_reg(vcpu, PMCR_EL0);
 	val = (pmcr >> ARMV8_PMU_PMCR_N_SHIFT) & ARMV8_PMU_PMCR_N_MASK;
 	if (idx >= val && idx != ARMV8_PMU_CYCLE_IDX) {
 		kvm_inject_undefined(vcpu);
@@ -629,7 +630,7 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
 			if (pmu_access_event_counter_el0_disabled(vcpu))
 				return false;
 
-			idx = vcpu_sys_reg(vcpu, PMSELR_EL0)
+			idx = __vcpu_sys_reg(vcpu, PMSELR_EL0)
 			      & ARMV8_PMU_COUNTER_MASK;
 		} else if (r->Op2 == 0) {
 			/* PMCCNTR_EL0 */
@@ -684,7 +685,7 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 
 	if (r->CRn == 9 && r->CRm == 13 && r->Op2 == 1) {
 		/* PMXEVTYPER_EL0 */
-		idx = vcpu_sys_reg(vcpu, PMSELR_EL0) & ARMV8_PMU_COUNTER_MASK;
+		idx = __vcpu_sys_reg(vcpu, PMSELR_EL0) & ARMV8_PMU_COUNTER_MASK;
 		reg = PMEVTYPER0_EL0 + idx;
 	} else if (r->CRn == 14 && (r->CRm & 12) == 12) {
 		idx = ((r->CRm & 3) << 3) | (r->Op2 & 7);
@@ -702,9 +703,9 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 
 	if (p->is_write) {
 		kvm_pmu_set_counter_event_type(vcpu, p->regval, idx);
-		vcpu_sys_reg(vcpu, reg) = p->regval & ARMV8_PMU_EVTYPE_MASK;
+		__vcpu_sys_reg(vcpu, reg) = p->regval & ARMV8_PMU_EVTYPE_MASK;
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, reg) & ARMV8_PMU_EVTYPE_MASK;
+		p->regval = __vcpu_sys_reg(vcpu, reg) & ARMV8_PMU_EVTYPE_MASK;
 	}
 
 	return true;
@@ -726,15 +727,15 @@ static bool access_pmcnten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		val = p->regval & mask;
 		if (r->Op2 & 0x1) {
 			/* accessing PMCNTENSET_EL0 */
-			vcpu_sys_reg(vcpu, PMCNTENSET_EL0) |= val;
+			__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) |= val;
 			kvm_pmu_enable_counter(vcpu, val);
 		} else {
 			/* accessing PMCNTENCLR_EL0 */
-			vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= ~val;
+			__vcpu_sys_reg(vcpu, PMCNTENSET_EL0) &= ~val;
 			kvm_pmu_disable_counter(vcpu, val);
 		}
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
+		p->regval = __vcpu_sys_reg(vcpu, PMCNTENSET_EL0) & mask;
 	}
 
 	return true;
@@ -758,12 +759,12 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 
 		if (r->Op2 & 0x1)
 			/* accessing PMINTENSET_EL1 */
-			vcpu_sys_reg(vcpu, PMINTENSET_EL1) |= val;
+			__vcpu_sys_reg(vcpu, PMINTENSET_EL1) |= val;
 		else
 			/* accessing PMINTENCLR_EL1 */
-			vcpu_sys_reg(vcpu, PMINTENSET_EL1) &= ~val;
+			__vcpu_sys_reg(vcpu, PMINTENSET_EL1) &= ~val;
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, PMINTENSET_EL1) & mask;
+		p->regval = __vcpu_sys_reg(vcpu, PMINTENSET_EL1) & mask;
 	}
 
 	return true;
@@ -783,12 +784,12 @@ static bool access_pmovs(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	if (p->is_write) {
 		if (r->CRm & 0x2)
 			/* accessing PMOVSSET_EL0 */
-			vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= (p->regval & mask);
+			__vcpu_sys_reg(vcpu, PMOVSSET_EL0) |= (p->regval & mask);
 		else
 			/* accessing PMOVSCLR_EL0 */
-			vcpu_sys_reg(vcpu, PMOVSSET_EL0) &= ~(p->regval & mask);
+			__vcpu_sys_reg(vcpu, PMOVSSET_EL0) &= ~(p->regval & mask);
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, PMOVSSET_EL0) & mask;
+		p->regval = __vcpu_sys_reg(vcpu, PMOVSSET_EL0) & mask;
 	}
 
 	return true;
@@ -825,10 +826,10 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 			return false;
 		}
 
-		vcpu_sys_reg(vcpu, PMUSERENR_EL0) = p->regval
-						    & ARMV8_PMU_USERENR_MASK;
+		__vcpu_sys_reg(vcpu, PMUSERENR_EL0) =
+			       p->regval & ARMV8_PMU_USERENR_MASK;
 	} else {
-		p->regval = vcpu_sys_reg(vcpu, PMUSERENR_EL0)
+		p->regval = __vcpu_sys_reg(vcpu, PMUSERENR_EL0)
 			    & ARMV8_PMU_USERENR_MASK;
 	}
 
@@ -2230,7 +2231,7 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (r->get_user)
 		return (r->get_user)(vcpu, r, reg, uaddr);
 
-	return reg_to_user(uaddr, &vcpu_sys_reg(vcpu, r->reg), reg->id);
+	return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
 }
 
 int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
@@ -2251,7 +2252,7 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 	if (r->set_user)
 		return (r->set_user)(vcpu, r, reg, uaddr);
 
-	return reg_from_user(&vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
+	return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
 }
 
 static unsigned int num_demux_regs(void)
@@ -2457,6 +2458,6 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
 	reset_sys_reg_descs(vcpu, table, num);
 
 	for (num = 1; num < NR_SYS_REGS; num++)
-		if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
-			panic("Didn't reset vcpu_sys_reg(%zi)", num);
+		if (__vcpu_sys_reg(vcpu, num) == 0x4242424242424242)
+			panic("Didn't reset __vcpu_sys_reg(%zi)", num);
 }
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 060f5348ef25..cd710f8b63e0 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -89,14 +89,14 @@ static inline void reset_unknown(struct kvm_vcpu *vcpu,
 {
 	BUG_ON(!r->reg);
 	BUG_ON(r->reg >= NR_SYS_REGS);
-	vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
+	__vcpu_sys_reg(vcpu, r->reg) = 0x1de7ec7edbadc0deULL;
 }
 
 static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
 	BUG_ON(!r->reg);
 	BUG_ON(r->reg >= NR_SYS_REGS);
-	vcpu_sys_reg(vcpu, r->reg) = r->val;
+	__vcpu_sys_reg(vcpu, r->reg) = r->val;
 }
 
 static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
diff --git a/arch/arm64/kvm/sys_regs_generic_v8.c b/arch/arm64/kvm/sys_regs_generic_v8.c
index 969ade1d333d..ddb8497d18d6 100644
--- a/arch/arm64/kvm/sys_regs_generic_v8.c
+++ b/arch/arm64/kvm/sys_regs_generic_v8.c
@@ -38,13 +38,13 @@ static bool access_actlr(struct kvm_vcpu *vcpu,
 	if (p->is_write)
 		return ignore_write(vcpu, p);
 
-	p->regval = vcpu_sys_reg(vcpu, ACTLR_EL1);
+	p->regval = vcpu_read_sys_reg(vcpu, ACTLR_EL1);
 	return true;
 }
 
 static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
-	vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);
+	__vcpu_sys_reg(vcpu, ACTLR_EL1) = read_sysreg(actlr_el1);
 }
 
 /*