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

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

Functions are slightly refactored to move code hidden behind `has_vhe()` checks
to the corresponding .c files.

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

Author: David Brazdil

arch/arm64/kernel/image-vars.h

@@ -66,11 +66,6 @@ __efistub__ctype		= _ctype;
 /* Symbols defined in aarch32.c (not yet compiled with nVHE build rules). */
 KVM_NVHE_ALIAS(kvm_skip_instr32);
 
-/* Symbols defined in debug-sr.c (not yet compiled with nVHE build rules). */
-KVM_NVHE_ALIAS(__debug_switch_to_guest);
-KVM_NVHE_ALIAS(__debug_switch_to_host);
-KVM_NVHE_ALIAS(__kvm_get_mdcr_el2);
-
 /* Symbols defined in entry.S (not yet compiled with nVHE build rules). */
 KVM_NVHE_ALIAS(__guest_enter);
 KVM_NVHE_ALIAS(__guest_exit);

arch/arm64/kvm/hyp/Makefile

@@ -14,7 +14,7 @@ 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 \
-	 debug-sr.o entry.o fpsimd.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/debug-sr.c renamed to arch/arm64/kvm/hyp/include/hyp/debug-sr.h

@@ -4,6 +4,9 @@
  * Author: Marc Zyngier <[email protected]>
  */
 
+#ifndef __ARM64_KVM_HYP_DEBUG_SR_H__
+#define __ARM64_KVM_HYP_DEBUG_SR_H__
+
 #include <linux/compiler.h>
 #include <linux/kvm_host.h>
 
@@ -85,53 +88,9 @@
 	default:	write_debug(ptr[0], reg, 0);			\
 	}
 
-static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1)
-{
-	u64 reg;
-
-	/* Clear pmscr in case of early return */
-	*pmscr_el1 = 0;
-
-	/* SPE present on this CPU? */
-	if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
-						  ID_AA64DFR0_PMSVER_SHIFT))
-		return;
-
-	/* Yes; is it owned by EL3? */
-	reg = read_sysreg_s(SYS_PMBIDR_EL1);
-	if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT))
-		return;
-
-	/* No; is the host actually using the thing? */
-	reg = read_sysreg_s(SYS_PMBLIMITR_EL1);
-	if (!(reg & BIT(SYS_PMBLIMITR_EL1_E_SHIFT)))
-		return;
-
-	/* Yes; save the control register and disable data generation */
-	*pmscr_el1 = read_sysreg_s(SYS_PMSCR_EL1);
-	write_sysreg_s(0, SYS_PMSCR_EL1);
-	isb();
-
-	/* Now drain all buffered data to memory */
-	psb_csync();
-	dsb(nsh);
-}
-
-static void __hyp_text __debug_restore_spe_nvhe(u64 pmscr_el1)
-{
-	if (!pmscr_el1)
-		return;
-
-	/* The host page table is installed, but not yet synchronised */
-	isb();
-
-	/* Re-enable data generation */
-	write_sysreg_s(pmscr_el1, SYS_PMSCR_EL1);
-}
-
-static void __hyp_text __debug_save_state(struct kvm_vcpu *vcpu,
-					  struct kvm_guest_debug_arch *dbg,
-					  struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __debug_save_state(struct kvm_vcpu *vcpu,
+						 struct kvm_guest_debug_arch *dbg,
+						 struct kvm_cpu_context *ctxt)
 {
 	u64 aa64dfr0;
 	int brps, wrps;
@@ -148,9 +107,9 @@ static void __hyp_text __debug_save_state(struct kvm_vcpu *vcpu,
 	ctxt->sys_regs[MDCCINT_EL1] = read_sysreg(mdccint_el1);
 }
 
-static void __hyp_text __debug_restore_state(struct kvm_vcpu *vcpu,
-					     struct kvm_guest_debug_arch *dbg,
-					     struct kvm_cpu_context *ctxt)
+static inline void __hyp_text __debug_restore_state(struct kvm_vcpu *vcpu,
+						    struct kvm_guest_debug_arch *dbg,
+						    struct kvm_cpu_context *ctxt)
 {
 	u64 aa64dfr0;
 	int brps, wrps;
@@ -168,20 +127,13 @@ static void __hyp_text __debug_restore_state(struct kvm_vcpu *vcpu,
 	write_sysreg(ctxt->sys_regs[MDCCINT_EL1], mdccint_el1);
 }
 
-void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu)
+static inline void __hyp_text __debug_switch_to_guest_common(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
-	/*
-	 * Non-VHE: Disable and flush SPE data generation
-	 * VHE: The vcpu can run, but it can't hide.
-	 */
-	if (!has_vhe())
-		__debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1);
-
 	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
@@ -194,16 +146,13 @@ void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu)
 	__debug_restore_state(vcpu, guest_dbg, guest_ctxt);
 }
 
-void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
+static inline void __hyp_text __debug_switch_to_host_common(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
-	if (!has_vhe())
-		__debug_restore_spe_nvhe(vcpu->arch.host_debug_state.pmscr_el1);
-
 	if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
 		return;
 
@@ -218,7 +167,4 @@ void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
 	vcpu->arch.flags &= ~KVM_ARM64_DEBUG_DIRTY;
 }
 
-u32 __hyp_text __kvm_get_mdcr_el2(void)
-{
-	return read_sysreg(mdcr_el2);
-}
+#endif /* __ARM64_KVM_HYP_DEBUG_SR_H__ */

arch/arm64/kvm/hyp/nvhe/Makefile

@@ -6,7 +6,7 @@
 asflags-y := -D__KVM_NVHE_HYPERVISOR__
 ccflags-y := -D__KVM_NVHE_HYPERVISOR__
 
-obj-y := switch.o tlb.o hyp-init.o ../hyp-entry.o
+obj-y := 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/debug-sr.c

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier <[email protected]>
+ */
+
+#include <hyp/debug-sr.h>
+
+#include <linux/compiler.h>
+#include <linux/kvm_host.h>
+
+#include <asm/debug-monitors.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+
+static void __hyp_text __debug_save_spe(u64 *pmscr_el1)
+{
+	u64 reg;
+
+	/* Clear pmscr in case of early return */
+	*pmscr_el1 = 0;
+
+	/* SPE present on this CPU? */
+	if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
+						  ID_AA64DFR0_PMSVER_SHIFT))
+		return;
+
+	/* Yes; is it owned by EL3? */
+	reg = read_sysreg_s(SYS_PMBIDR_EL1);
+	if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT))
+		return;
+
+	/* No; is the host actually using the thing? */
+	reg = read_sysreg_s(SYS_PMBLIMITR_EL1);
+	if (!(reg & BIT(SYS_PMBLIMITR_EL1_E_SHIFT)))
+		return;
+
+	/* Yes; save the control register and disable data generation */
+	*pmscr_el1 = read_sysreg_s(SYS_PMSCR_EL1);
+	write_sysreg_s(0, SYS_PMSCR_EL1);
+	isb();
+
+	/* Now drain all buffered data to memory */
+	psb_csync();
+	dsb(nsh);
+}
+
+static void __hyp_text __debug_restore_spe(u64 pmscr_el1)
+{
+	if (!pmscr_el1)
+		return;
+
+	/* The host page table is installed, but not yet synchronised */
+	isb();
+
+	/* Re-enable data generation */
+	write_sysreg_s(pmscr_el1, SYS_PMSCR_EL1);
+}
+
+void __hyp_text __debug_switch_to_guest(struct kvm_vcpu *vcpu)
+{
+	/* Disable and flush SPE data generation */
+	__debug_save_spe(&vcpu->arch.host_debug_state.pmscr_el1);
+	__debug_switch_to_guest_common(vcpu);
+}
+
+void __hyp_text __debug_switch_to_host(struct kvm_vcpu *vcpu)
+{
+	__debug_restore_spe(vcpu->arch.host_debug_state.pmscr_el1);
+	__debug_switch_to_host_common(vcpu);
+}
+
+u32 __hyp_text __kvm_get_mdcr_el2(void)
+{
+	return read_sysreg(mdcr_el2);
+}

arch/arm64/kvm/hyp/vhe/Makefile

@@ -6,7 +6,7 @@
 asflags-y := -D__KVM_VHE_HYPERVISOR__
 ccflags-y := -D__KVM_VHE_HYPERVISOR__
 
-obj-y := switch.o tlb.o ../hyp-entry.o
+obj-y := 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/debug-sr.c

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier <[email protected]>
+ */
+
+#include <hyp/debug-sr.h>
+
+#include <linux/kvm_host.h>
+
+#include <asm/kvm_hyp.h>
+
+void __debug_switch_to_guest(struct kvm_vcpu *vcpu)
+{
+	__debug_switch_to_guest_common(vcpu);
+}
+
+void __debug_switch_to_host(struct kvm_vcpu *vcpu)
+{
+	__debug_switch_to_host_common(vcpu);
+}
+
+u32 __kvm_get_mdcr_el2(void)
+{
+	return read_sysreg(mdcr_el2);
+}