KVM: arm64: Add basic hooks for injecting exceptions from EL2

Add the basic infrastructure to describe injection of exceptions
into a guest. So far, nothing uses this code path.

Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 0672b3d..7a1faf9 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -407,9 +407,33 @@ struct kvm_vcpu_arch {
 #define KVM_ARM64_GUEST_HAS_SVE                (1 << 5) /* SVE exposed to guest */
 #define KVM_ARM64_VCPU_SVE_FINALIZED   (1 << 6) /* SVE config completed */
 #define KVM_ARM64_GUEST_HAS_PTRAUTH    (1 << 7) /* PTRAUTH exposed to guest */
-#define KVM_ARM64_INCREMENT_PC         (1 << 8) /* Increment PC */
+#define KVM_ARM64_PENDING_EXCEPTION    (1 << 8) /* Exception pending */
+#define KVM_ARM64_EXCEPT_MASK          (7 << 9) /* Target EL/MODE */
 
-#define vcpu_has_sve(vcpu) (system_supports_sve() && \
+/*
+ * When KVM_ARM64_PENDING_EXCEPTION is set, KVM_ARM64_EXCEPT_MASK can
+ * take the following values:
+ *
+ * For AArch32 EL1:
+ */
+#define KVM_ARM64_EXCEPT_AA32_UND      (0 << 9)
+#define KVM_ARM64_EXCEPT_AA32_IABT     (1 << 9)
+#define KVM_ARM64_EXCEPT_AA32_DABT     (2 << 9)
+/* For AArch64: */
+#define KVM_ARM64_EXCEPT_AA64_ELx_SYNC (0 << 9)
+#define KVM_ARM64_EXCEPT_AA64_ELx_IRQ  (1 << 9)
+#define KVM_ARM64_EXCEPT_AA64_ELx_FIQ  (2 << 9)
+#define KVM_ARM64_EXCEPT_AA64_ELx_SERR (3 << 9)
+#define KVM_ARM64_EXCEPT_AA64_EL1      (0 << 11)
+#define KVM_ARM64_EXCEPT_AA64_EL2      (1 << 11)
+
+/*
+ * Overlaps with KVM_ARM64_EXCEPT_MASK on purpose so that it can't be
+ * set together with an exception...
+ */
+#define KVM_ARM64_INCREMENT_PC         (1 << 9) /* Increment PC */
+
+#define vcpu_has_sve(vcpu) (system_supports_sve() &&                   \
                            ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
 
 #ifdef CONFIG_ARM64_PTR_AUTH

diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
new file mode 100644 (file)
index 0000000..6533a92
--- /dev/null
+++ b/arch/arm64/kvm/hyp/exception.c
@@ -0,0 +1,17 @@
+// 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>
+
+void kvm_inject_exception(struct kvm_vcpu *vcpu)
+{
+}

diff --git a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
index d3043b0..b1f6092 100644 (file)
--- a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
+++ b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
@@ -13,6 +13,8 @@
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_host.h>
 
+void kvm_inject_exception(struct kvm_vcpu *vcpu);
+
 static inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
 {
        if (vcpu_mode_is_32bit(vcpu)) {
@@ -43,11 +45,15 @@ static inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
 
 /*
  * Adjust the guest PC on entry, depending on flags provided by EL1
- * for the purpose of emulation (MMIO, sysreg).
+ * for the purpose of emulation (MMIO, sysreg) or exception injection.
  */
 static inline void __adjust_pc(struct kvm_vcpu *vcpu)
 {
-       if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
+       if (vcpu->arch.flags & KVM_ARM64_PENDING_EXCEPTION) {
+               kvm_inject_exception(vcpu);
+               vcpu->arch.flags &= ~(KVM_ARM64_PENDING_EXCEPTION |
+                                     KVM_ARM64_EXCEPT_MASK);
+       } else  if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
                kvm_skip_instr(vcpu);
                vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
        }

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index ddde15f..77b8c4e 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -8,7 +8,7 @@ ccflags-y := -D__KVM_NVHE_HYPERVISOR__
 
 obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o hyp-main.o
 obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
-        ../fpsimd.o ../hyp-entry.o
+        ../fpsimd.o ../hyp-entry.o ../exception.o
 
 ##
 ## Build rules for compiling nVHE hyp code

diff --git a/arch/arm64/kvm/hyp/vhe/Makefile b/arch/arm64/kvm/hyp/vhe/Makefile
index 461e97c..96bec0e 100644 (file)
--- a/arch/arm64/kvm/hyp/vhe/Makefile
+++ b/arch/arm64/kvm/hyp/vhe/Makefile
@@ -8,4 +8,4 @@ ccflags-y := -D__KVM_VHE_HYPERVISOR__
 
 obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o
 obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
-        ../fpsimd.o ../hyp-entry.o
+        ../fpsimd.o ../hyp-entry.o ../exception.o