KVM: arm64: Split hyp/sysreg-sr.c to VHE/nVHE

sysreg-sr.c contains KVM's code for saving/restoring system registers, with
some code shared between VHE/nVHE. These common routines are moved to
a header file, VHE-specific code is moved to vhe/sysreg-sr.c and nVHE-specific
code to nvhe/sysreg-sr.c.

Signed-off-by: David Brazdil <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm64/include/asm/kvm_host.h

···
 	struct vcpu_reset_state	reset_state;
 
 	/* True when deferrable sysregs are loaded on the physical CPU,
-	 * see kvm_vcpu_load_sysregs and kvm_vcpu_put_sysregs. */
+	 * see kvm_vcpu_load_sysregs_vhe and kvm_vcpu_put_sysregs_vhe. */
 	bool sysregs_loaded_on_cpu;
 
 	/* Guest PV state */
···
 	}
 }
 
-void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);
-void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);
+void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu);
+void kvm_vcpu_put_sysregs_vhe(struct kvm_vcpu *vcpu);
 
 int kvm_set_ipa_limit(void);
 

arch/arm64/include/asm/kvm_hyp.h

···
 void __timer_enable_traps(struct kvm_vcpu *vcpu);
 void __timer_disable_traps(struct kvm_vcpu *vcpu);
 
+#ifdef __KVM_NVHE_HYPERVISOR__
 void __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt);
 void __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt);
+#else
 void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt);
 void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt);
 void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt);
 void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt);
-void __sysreg32_save_state(struct kvm_vcpu *vcpu);
-void __sysreg32_restore_state(struct kvm_vcpu *vcpu);
+#endif
 
 void __debug_switch_to_guest(struct kvm_vcpu *vcpu);
 void __debug_switch_to_host(struct kvm_vcpu *vcpu);

arch/arm64/kernel/image-vars.h

···
 KVM_NVHE_ALIAS(__fpsimd_restore_state);
 KVM_NVHE_ALIAS(__fpsimd_save_state);
 
-/* Symbols defined in sysreg-sr.c (not yet compiled with nVHE build rules). */
-KVM_NVHE_ALIAS(__kvm_enable_ssbs);
-KVM_NVHE_ALIAS(__sysreg32_restore_state);
-KVM_NVHE_ALIAS(__sysreg32_save_state);
-KVM_NVHE_ALIAS(__sysreg_restore_state_nvhe);
-KVM_NVHE_ALIAS(__sysreg_save_state_nvhe);
-
 /* Symbols defined in timer-sr.c (not yet compiled with nVHE build rules). */
 KVM_NVHE_ALIAS(__kvm_timer_set_cntvoff);
 KVM_NVHE_ALIAS(__timer_disable_traps);

arch/arm64/kvm/arm.c

···
 
 	kvm_vgic_load(vcpu);
 	kvm_timer_vcpu_load(vcpu);
-	kvm_vcpu_load_sysregs(vcpu);
+	if (has_vhe())
+		kvm_vcpu_load_sysregs_vhe(vcpu);
 	kvm_arch_vcpu_load_fp(vcpu);
 	kvm_vcpu_pmu_restore_guest(vcpu);
 	if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
···
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
 	kvm_arch_vcpu_put_fp(vcpu);
-	kvm_vcpu_put_sysregs(vcpu);
+	if (has_vhe())
+		kvm_vcpu_put_sysregs_vhe(vcpu);
 	kvm_timer_vcpu_put(vcpu);
 	kvm_vgic_put(vcpu);
 	kvm_vcpu_pmu_restore_host(vcpu);
···
 	 */
 	if (this_cpu_has_cap(ARM64_SSBS) &&
 	    arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
-		kvm_call_hyp(__kvm_enable_ssbs);
+		kvm_call_hyp_nvhe(__kvm_enable_ssbs);
 	}
 }
 

arch/arm64/kvm/hyp/Makefile

···
 obj-$(CONFIG_KVM) += hyp.o vhe/ nvhe/
 obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o
 
-hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \
-	 entry.o fpsimd.o
+hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o entry.o \
+	 fpsimd.o
 
 # KVM code is run at a different exception code with a different map, so
 # compiler instrumentation that inserts callbacks or checks into the code may

arch/arm64/kvm/hyp/nvhe/Makefile

···
 asflags-y := -D__KVM_NVHE_HYPERVISOR__
 ccflags-y := -D__KVM_NVHE_HYPERVISOR__
 
-obj-y := debug-sr.o switch.o tlb.o hyp-init.o ../hyp-entry.o
+obj-y := sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o ../hyp-entry.o
 
 obj-y := $(patsubst %.o,%.hyp.o,$(obj-y))
 extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y))

arch/arm64/kvm/hyp/nvhe/switch.c

···
  */
 
 #include <hyp/switch.h>
+#include <hyp/sysreg-sr.h>
 
 #include <linux/arm-smccc.h>
 #include <linux/kvm_host.h>

arch/arm64/kvm/hyp/nvhe/sysreg-sr.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012-2015 - ARM Ltd
+ * Author: Marc Zyngier <[e-mail]>
+ */
+
+#include <hyp/sysreg-sr.h>
+
+#include <linux/compiler.h>
+#include <linux/kvm_host.h>
+
+#include <asm/kprobes.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_hyp.h>
+
+/*
+ * Non-VHE: Both host and guest must save everything.
+ */
+
+void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_el1_state(ctxt);
+	__sysreg_save_common_state(ctxt);
+	__sysreg_save_user_state(ctxt);
+	__sysreg_save_el2_return_state(ctxt);
+}
+
+void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_el1_state(ctxt);
+	__sysreg_restore_common_state(ctxt);
+	__sysreg_restore_user_state(ctxt);
+	__sysreg_restore_el2_return_state(ctxt);
+}
+
+void __hyp_text __kvm_enable_ssbs(void)
+{
+	u64 tmp;
+
+	asm volatile(
+	"mrs	%0, sctlr_el2\n"
+	"orr	%0, %0, %1\n"
+	"msr	sctlr_el2, %0"
+	: "=&r" (tmp) : "L" (SCTLR_ELx_DSSBS));
+}

arch/arm64/kvm/hyp/sysreg-sr.c arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h

···
  * Author: Marc Zyngier <[e-mail]>
  */
 
+#ifndef __ARM64_KVM_HYP_SYSREG_SR_H__
+#define __ARM64_KVM_HYP_SYSREG_SR_H__
+
 #include <linux/compiler.h>
 #include <linux/kvm_host.h>
 
···
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 
-/*
- * Non-VHE: Both host and guest must save everything.
- *
- * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and
- * pstate, which are handled as part of the el2 return state) on every
- * switch (sp_el0 is being dealt with in the assembly code).
- * tpidr_el0 and tpidrro_el0 only need to be switched when going
- * to host userspace or a different VCPU.  EL1 registers only need to be
- * switched when potentially going to run a different VCPU.  The latter two
- * classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
- */
-
-static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);
 }
 
-static void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);
 	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);
 }
 
-static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->sys_regs[CSSELR_EL1]	= read_sysreg(csselr_el1);
 	ctxt->sys_regs[SCTLR_EL1]	= read_sysreg_el1(SYS_SCTLR);
···
 	ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(SYS_SPSR);
 }
 
-static void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt->gp_regs.regs.pc		= read_sysreg_el2(SYS_ELR);
 	ctxt->gp_regs.regs.pstate	= read_sysreg_el2(SYS_SPSR);
···
 		ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
 }
 
-void __hyp_text __sysreg_save_state_nvhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_save_el1_state(ctxt);
-	__sysreg_save_common_state(ctxt);
-	__sysreg_save_user_state(ctxt);
-	__sysreg_save_el2_return_state(ctxt);
-}
-
-void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_save_common_state(ctxt);
-}
-NOKPROBE_SYMBOL(sysreg_save_host_state_vhe);
-
-void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_save_common_state(ctxt);
-	__sysreg_save_el2_return_state(ctxt);
-}
-NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
-
-static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);
 }
 
-static void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[TPIDR_EL0],		tpidr_el0);
 	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0],	tpidrro_el0);
 }
 
-static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt->sys_regs[MPIDR_EL1],		vmpidr_el2);
 	write_sysreg(ctxt->sys_regs[CSSELR_EL1],	csselr_el1);
···
 	write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],SYS_SPSR);
 }
 
-static void __hyp_text
-__sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __sysreg_restore_el2_return_state(struct kvm_cpu_context *ctxt)
 {
 	u64 pstate = ctxt->gp_regs.regs.pstate;
 	u64 mode = pstate & PSR_AA32_MODE_MASK;
···
 		write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
 }
 
-void __hyp_text __sysreg_restore_state_nvhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_restore_el1_state(ctxt);
-	__sysreg_restore_common_state(ctxt);
-	__sysreg_restore_user_state(ctxt);
-	__sysreg_restore_el2_return_state(ctxt);
-}
-
-void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_restore_common_state(ctxt);
-}
-NOKPROBE_SYMBOL(sysreg_restore_host_state_vhe);
-
-void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
-{
-	__sysreg_restore_common_state(ctxt);
-	__sysreg_restore_el2_return_state(ctxt);
-}
-NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe);
-
-void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
+static inline void __hyp_text __sysreg32_save_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;
 
···
 		sysreg[DBGVCR32_EL2] = read_sysreg(dbgvcr32_el2);
 }
 
-void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
+static inline void __hyp_text __sysreg32_restore_state(struct kvm_vcpu *vcpu)
 {
 	u64 *spsr, *sysreg;
 
···
 		write_sysreg(sysreg[DBGVCR32_EL2], dbgvcr32_el2);
 }
 
-/**
- * kvm_vcpu_load_sysregs - Load guest system registers to the physical CPU
- *
- * @vcpu: The VCPU pointer
- *
- * Load system registers that do not affect the host's execution, for
- * example EL1 system registers on a VHE system where the host kernel
- * runs at EL2.  This function is called from KVM's vcpu_load() function
- * and loading system register state early avoids having to load them on
- * every entry to the VM.
- */
-void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu)
-{
-	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
-	struct kvm_cpu_context *host_ctxt;
-
-	if (!has_vhe())
-		return;
-
-	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
-	__sysreg_save_user_state(host_ctxt);
-
-	/*
-	 * Load guest EL1 and user state
-	 *
-	 * We must restore the 32-bit state before the sysregs, thanks
-	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
-	 */
-	__sysreg32_restore_state(vcpu);
-	__sysreg_restore_user_state(guest_ctxt);
-	__sysreg_restore_el1_state(guest_ctxt);
-
-	vcpu->arch.sysregs_loaded_on_cpu = true;
-
-	activate_traps_vhe_load(vcpu);
-}
-
-/**
- * kvm_vcpu_put_sysregs - Restore host system registers to the physical CPU
- *
- * @vcpu: The VCPU pointer
- *
- * Save guest system registers that do not affect the host's execution, for
- * example EL1 system registers on a VHE system where the host kernel
- * runs at EL2.  This function is called from KVM's vcpu_put() function
- * and deferring saving system register state until we're no longer running the
- * VCPU avoids having to save them on every exit from the VM.
- */
-void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu)
-{
-	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
-	struct kvm_cpu_context *host_ctxt;
-
-	if (!has_vhe())
-		return;
-
-	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
-	deactivate_traps_vhe_put();
-
-	__sysreg_save_el1_state(guest_ctxt);
-	__sysreg_save_user_state(guest_ctxt);
-	__sysreg32_save_state(vcpu);
-
-	/* Restore host user state */
-	__sysreg_restore_user_state(host_ctxt);
-
-	vcpu->arch.sysregs_loaded_on_cpu = false;
-}
-
-void __hyp_text __kvm_enable_ssbs(void)
-{
-	u64 tmp;
-
-	asm volatile(
-	"mrs	%0, sctlr_el2\n"
-	"orr	%0, %0, %1\n"
-	"msr	sctlr_el2, %0"
-	: "=&r" (tmp) : "L" (SCTLR_ELx_DSSBS));
-}
+#endif /* __ARM64_KVM_HYP_SYSREG_SR_H__ */

arch/arm64/kvm/hyp/vhe/Makefile

···
 asflags-y := -D__KVM_VHE_HYPERVISOR__
 ccflags-y := -D__KVM_VHE_HYPERVISOR__
 
-obj-y := debug-sr.o switch.o tlb.o ../hyp-entry.o
+obj-y := sysreg-sr.o debug-sr.o switch.o tlb.o ../hyp-entry.o
 
 # KVM code is run at a different exception code with a different map, so
 # compiler instrumentation that inserts callbacks or checks into the code may

arch/arm64/kvm/hyp/vhe/switch.c

···
 	 * HCR_EL2.TGE.
 	 *
 	 * We have already configured the guest's stage 1 translation in
-	 * kvm_vcpu_load_sysregs above.  We must now call __activate_vm
+	 * kvm_vcpu_load_sysregs_vhe above.  We must now call __activate_vm
 	 * before __activate_traps, because __activate_vm configures
 	 * stage 2 translation, and __activate_traps clear HCR_EL2.TGE
 	 * (among other things).

arch/arm64/kvm/hyp/vhe/sysreg-sr.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012-2015 - ARM Ltd
+ * Author: Marc Zyngier <[e-mail]>
+ */
+
+#include <hyp/sysreg-sr.h>
+
+#include <linux/compiler.h>
+#include <linux/kvm_host.h>
+
+#include <asm/kprobes.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_hyp.h>
+
+/*
+ * VHE: Host and guest must save mdscr_el1 and sp_el0 (and the PC and
+ * pstate, which are handled as part of the el2 return state) on every
+ * switch (sp_el0 is being dealt with in the assembly code).
+ * tpidr_el0 and tpidrro_el0 only need to be switched when going
+ * to host userspace or a different VCPU.  EL1 registers only need to be
+ * switched when potentially going to run a different VCPU.  The latter two
+ * classes are handled as part of kvm_arch_vcpu_load and kvm_arch_vcpu_put.
+ */
+
+void sysreg_save_host_state_vhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_common_state(ctxt);
+}
+NOKPROBE_SYMBOL(sysreg_save_host_state_vhe);
+
+void sysreg_save_guest_state_vhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_save_common_state(ctxt);
+	__sysreg_save_el2_return_state(ctxt);
+}
+NOKPROBE_SYMBOL(sysreg_save_guest_state_vhe);
+
+void sysreg_restore_host_state_vhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_common_state(ctxt);
+}
+NOKPROBE_SYMBOL(sysreg_restore_host_state_vhe);
+
+void sysreg_restore_guest_state_vhe(struct kvm_cpu_context *ctxt)
+{
+	__sysreg_restore_common_state(ctxt);
+	__sysreg_restore_el2_return_state(ctxt);
+}
+NOKPROBE_SYMBOL(sysreg_restore_guest_state_vhe);
+
+/**
+ * kvm_vcpu_load_sysregs_vhe - Load guest system registers to the physical CPU
+ *
+ * @vcpu: The VCPU pointer
+ *
+ * Load system registers that do not affect the host's execution, for
+ * example EL1 system registers on a VHE system where the host kernel
+ * runs at EL2.  This function is called from KVM's vcpu_load() function
+ * and loading system register state early avoids having to load them on
+ * every entry to the VM.
+ */
+void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
+	struct kvm_cpu_context *host_ctxt;
+
+	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+	__sysreg_save_user_state(host_ctxt);
+
+	/*
+	 * Load guest EL1 and user state
+	 *
+	 * We must restore the 32-bit state before the sysregs, thanks
+	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
+	 */
+	__sysreg32_restore_state(vcpu);
+	__sysreg_restore_user_state(guest_ctxt);
+	__sysreg_restore_el1_state(guest_ctxt);
+
+	vcpu->arch.sysregs_loaded_on_cpu = true;
+
+	activate_traps_vhe_load(vcpu);
+}
+
+/**
+ * kvm_vcpu_put_sysregs_vhe - Restore host system registers to the physical CPU
+ *
+ * @vcpu: The VCPU pointer
+ *
+ * Save guest system registers that do not affect the host's execution, for
+ * example EL1 system registers on a VHE system where the host kernel
+ * runs at EL2.  This function is called from KVM's vcpu_put() function
+ * and deferring saving system register state until we're no longer running the
+ * VCPU avoids having to save them on every exit from the VM.
+ */
+void kvm_vcpu_put_sysregs_vhe(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
+	struct kvm_cpu_context *host_ctxt;
+
+	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+	deactivate_traps_vhe_put();
+
+	__sysreg_save_el1_state(guest_ctxt);
+	__sysreg_save_user_state(guest_ctxt);
+	__sysreg32_save_state(vcpu);
+
+	/* Restore host user state */
+	__sysreg_restore_user_state(host_ctxt);
+
+	vcpu->arch.sysregs_loaded_on_cpu = false;
+}