[PATCH v2 11/28] KVM: arm64: Access elements of vcpu_gp_regs individually

[Steffen Eiden <seiden@linux.ibm.com>]

While for arm64 the members of vcpu_gp_regs are allocated continuous
this is not necessarily true for other architectures implementing ARM.

Let vcpu_gp_regs() no longer return the address of the user_pt_regs in
the vcpu context but the address of the gp-register array field in the
user_pt_reg struct.

Co-developed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
---
 arch/arm64/include/asm/kvm_emulate.h       | 9 +++++++--
 arch/arm64/include/asm/kvm_host.h          | 2 +-
 arch/arm64/kvm/hyp/exception.c             | 7 +++++--
 arch/arm64/kvm/hyp/include/hyp/adjust_pc.h | 4 ++--
 arch/arm64/kvm/hyp/include/hyp/switch.h    | 6 +++---
 arch/arm64/kvm/reset.c                     | 6 ++++--
 include/kvm/arm64/kvm_emulate.h            | 4 ++--
 virt/kvm/arm64/guest.c                     | 6 +++---
 8 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 39fa3a12730c..41eac2b5de14 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -95,12 +95,17 @@ static inline void vcpu_set_vsesr(struct kvm_vcpu *vcpu, u64 vsesr)
 
 static __always_inline unsigned long *vcpu_pc(const struct kvm_vcpu *vcpu)
 {
-	return (unsigned long *)&vcpu_gp_regs(vcpu)->pc;
+	return (unsigned long *)&vcpu->arch.ctxt.regs.pc;
 }
 
 static __always_inline unsigned long *vcpu_cpsr(const struct kvm_vcpu *vcpu)
 {
-	return (unsigned long *)&vcpu_gp_regs(vcpu)->pstate;
+	return (unsigned long *)&vcpu->arch.ctxt.regs.pstate;
+}
+
+static __always_inline unsigned long *vcpu_sp_el0(const struct kvm_vcpu *vcpu)
+{
+	return (unsigned long *)&vcpu->arch.ctxt.regs.sp;
 }
 
 static __always_inline bool vcpu_mode_is_32bit(const struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ae9e507f2c7c..7e473b895740 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1050,7 +1050,7 @@ struct kvm_vcpu_arch {
 #define vcpu_clear_on_unsupported_cpu(vcpu)				\
 	vcpu_clear_flag(vcpu, ON_UNSUPPORTED_CPU)
 
-#define vcpu_gp_regs(v)		(&(v)->arch.ctxt.regs)
+#define vcpu_gp_regs(v)		((v)->arch.ctxt.regs.regs)
 
 /*
  * Only use __vcpu_sys_reg/ctxt_sys_reg if you know you want the
diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
index bef40ddb16db..82611442a2d1 100644
--- a/arch/arm64/kvm/hyp/exception.c
+++ b/arch/arm64/kvm/hyp/exception.c
@@ -277,6 +277,9 @@ static const u8 return_offsets[8][2] = {
 	[7] = { 4, 4 },		/* FIQ, unused */
 };
 
+#define OFFSETOF_PT_REG(__r) offsetof(struct user_pt_regs, __r)
+#define COMPAT_IDX(__c) ((OFFSETOF_PT_REG(__c) - OFFSETOF_PT_REG(regs[0])) / sizeof(u64))
+
 static void enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
 {
 	unsigned long spsr = *vcpu_cpsr(vcpu);
@@ -292,12 +295,12 @@ static void enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
 	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;
+		vcpu_gp_regs(vcpu)[COMPAT_IDX(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;
+		vcpu_gp_regs(vcpu)[COMPAT_IDX(compat_lr_und)] = return_address;
 		break;
 	}
 
diff --git a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
index 15e1e5db73e1..4e4cb67824c0 100644
--- a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
+++ b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
@@ -20,11 +20,11 @@
 static inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
 {
 	*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
-	vcpu_gp_regs(vcpu)->pstate = read_sysreg_el2(SYS_SPSR);
+	*vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR);
 
 	kvm_skip_instr(vcpu);
 
-	write_sysreg_el2(vcpu_gp_regs(vcpu)->pstate, SYS_SPSR);
+	write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR);
 	write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
 }
 
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 2597e8bda867..6250b50e1841 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -416,7 +416,7 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
 static inline bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
-	arm64_mops_reset_regs(vcpu_gp_regs(vcpu), vcpu->arch.fault.esr_el2);
+	arm64_mops_reset_regs(&vcpu->arch.ctxt.regs, vcpu->arch.fault.esr_el2);
 	write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
 
 	/*
@@ -857,7 +857,7 @@ static inline void synchronize_vcpu_pstate(struct kvm_vcpu *vcpu)
 	/*
 	 * Check for the conditions of Cortex-A510's #2077057. When these occur
 	 * SPSR_EL2 can't be trusted, but isn't needed either as it is
-	 * unchanged from the value in vcpu_gp_regs(vcpu)->pstate.
+	 * unchanged from the value in vcpu_cpsr(vcpu).
 	 * Are we single-stepping the guest, and took a PAC exception from the
 	 * active-not-pending state?
 	 */
@@ -867,7 +867,7 @@ static inline void synchronize_vcpu_pstate(struct kvm_vcpu *vcpu)
 	    ESR_ELx_EC(read_sysreg_el2(SYS_ESR)) == ESR_ELx_EC_PAC)
 		write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR);
 
-	vcpu->arch.ctxt.regs.pstate = read_sysreg_el2(SYS_SPSR);
+	*vcpu_cpsr(vcpu) = read_sysreg_el2(SYS_SPSR);
 }
 
 /*
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 036bf2dff976..e952dec01d74 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -218,13 +218,15 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		pstate = VCPU_RESET_PSTATE_EL1;
 
 	/* Reset core registers */
-	memset(vcpu_gp_regs(vcpu), 0, sizeof(*vcpu_gp_regs(vcpu)));
+	memset(vcpu_gp_regs(vcpu), 0, sizeof(vcpu_gp_regs(vcpu)));
+	*vcpu_pc(vcpu) = 0;
+	*vcpu_sp_el0(vcpu) = 0;
 	memset(&vcpu->arch.ctxt.fp_regs, 0, sizeof(vcpu->arch.ctxt.fp_regs));
 	vcpu->arch.ctxt.spsr_abt = 0;
 	vcpu->arch.ctxt.spsr_und = 0;
 	vcpu->arch.ctxt.spsr_irq = 0;
 	vcpu->arch.ctxt.spsr_fiq = 0;
-	vcpu_gp_regs(vcpu)->pstate = pstate;
+	*vcpu_cpsr(vcpu) = pstate;
 
 	/* Reset system registers */
 	kvm_reset_sys_regs(vcpu);
diff --git a/include/kvm/arm64/kvm_emulate.h b/include/kvm/arm64/kvm_emulate.h
index 25322b95af21..0e16d18e53d2 100644
--- a/include/kvm/arm64/kvm_emulate.h
+++ b/include/kvm/arm64/kvm_emulate.h
@@ -77,14 +77,14 @@ static inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
 static __always_inline unsigned long vcpu_get_reg(const struct kvm_vcpu *vcpu,
 						  u8 reg_num)
 {
-	return (reg_num == 31) ? 0 : vcpu_gp_regs(vcpu)->regs[reg_num];
+	return (reg_num == 31) ? 0 : vcpu_gp_regs(vcpu)[reg_num];
 }
 
 static __always_inline void vcpu_set_reg(struct kvm_vcpu *vcpu, u8 reg_num,
 					 unsigned long val)
 {
 	if (reg_num != 31)
-		vcpu_gp_regs(vcpu)->regs[reg_num] = val;
+		vcpu_gp_regs(vcpu)[reg_num] = val;
 }
 
 static inline u32 kvm_vcpu_hvc_get_imm(const struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/arm64/guest.c b/virt/kvm/arm64/guest.c
index 83e33e0143b9..e283a4456df8 100644
--- a/virt/kvm/arm64/guest.c
+++ b/virt/kvm/arm64/guest.c
@@ -81,16 +81,16 @@ static void *core_reg_addr(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	     KVM_REG_ARM_CORE_REG(regs.regs[30]):
 		off -= KVM_REG_ARM_CORE_REG(regs.regs[0]);
 		off /= 2;
-		return &vcpu_gp_regs(vcpu)->regs[off];
+		return &vcpu_gp_regs(vcpu)[off];
 
 	case KVM_REG_ARM_CORE_REG(regs.sp):
-		return &vcpu_gp_regs(vcpu)->sp;
+		return vcpu_sp_el0(vcpu);
 
 	case KVM_REG_ARM_CORE_REG(regs.pc):
 		return vcpu_pc(vcpu);
 
 	case KVM_REG_ARM_CORE_REG(regs.pstate):
-		return &vcpu_gp_regs(vcpu)->pstate;
+		return vcpu_cpsr(vcpu);
 
 	case KVM_REG_ARM_CORE_REG(sp_el1):
 		return __ctxt_sys_reg(&vcpu->arch.ctxt, SP_EL1);
-- 
2.51.0