Merge branch 'kvm-arm64/vector-rework' into kvmarm-master/next

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

5 files changed, 64 insertions, 81 deletions

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index e7d98997c09c..162539d4c8cd 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -21,7 +21,7 @@
 #define ARM64_HAS_VIRT_HOST_EXTN		11
 #define ARM64_WORKAROUND_CAVIUM_27456		12
 #define ARM64_HAS_32BIT_EL0			13
-#define ARM64_HARDEN_EL2_VECTORS		14
+#define ARM64_SPECTRE_V3A			14
 #define ARM64_HAS_CNP				15
 #define ARM64_HAS_NO_FPSIMD			16
 #define ARM64_WORKAROUND_REPEAT_TLBI		17
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index a542c422a036..4a6a77d8d13e 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -34,8 +34,6 @@
  */
 #define KVM_VECTOR_PREAMBLE	(2 * AARCH64_INSN_SIZE)
 
-#define __SMCCC_WORKAROUND_1_SMC_SZ 36
-
 #define KVM_HOST_SMCCC_ID(id)						\
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
 			   ARM_SMCCC_SMC_64,				\
@@ -175,7 +173,6 @@ extern unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 DECLARE_KVM_NVHE_SYM(__per_cpu_start);
 DECLARE_KVM_NVHE_SYM(__per_cpu_end);
 
-extern atomic_t arm64_el2_vector_last_slot;
 DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
 #define __bp_harden_hyp_vecs	CHOOSE_HYP_SYM(__bp_harden_hyp_vecs)
 
@@ -196,8 +193,6 @@ extern void __vgic_v3_init_lrs(void);
 
 extern u32 __kvm_get_mdcr_el2(void);
 
-extern char __smccc_workaround_1_smc[__SMCCC_WORKAROUND_1_SMC_SZ];
-
 /*
  * Obtain the PC-relative address of a kernel symbol
  * s: symbol
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 5633c5a27aad..e298191a854d 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -248,52 +248,6 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
 	return ret;
 }
 
-/*
- * EL2 vectors can be mapped and rerouted in a number of ways,
- * depending on the kernel configuration and CPU present:
- *
- * - If the CPU is affected by Spectre-v2, the hardening sequence is
- *   placed in one of the vector slots, which is executed before jumping
- *   to the real vectors.
- *
- * - If the CPU also has the ARM64_HARDEN_EL2_VECTORS cap, the slot
- *   containing the hardening sequence is mapped next to the idmap page,
- *   and executed before jumping to the real vectors.
- *
- * - If the CPU only has the ARM64_HARDEN_EL2_VECTORS cap, then an
- *   empty slot is selected, mapped next to the idmap page, and
- *   executed before jumping to the real vectors.
- *
- * Note that ARM64_HARDEN_EL2_VECTORS is somewhat incompatible with
- * VHE, as we don't have hypervisor-specific mappings. If the system
- * is VHE and yet selects this capability, it will be ignored.
- */
-extern void *__kvm_bp_vect_base;
-extern int __kvm_harden_el2_vector_slot;
-
-static inline void *kvm_get_hyp_vector(void)
-{
-	struct bp_hardening_data *data = arm64_get_bp_hardening_data();
-	void *vect = kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
-	int slot = -1;
-
-	if (cpus_have_const_cap(ARM64_SPECTRE_V2) && data->fn) {
-		vect = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs));
-		slot = data->hyp_vectors_slot;
-	}
-
-	if (this_cpu_has_cap(ARM64_HARDEN_EL2_VECTORS) && !has_vhe()) {
-		vect = __kvm_bp_vect_base;
-		if (slot == -1)
-			slot = __kvm_harden_el2_vector_slot;
-	}
-
-	if (slot != -1)
-		vect += slot * SZ_2K;
-
-	return vect;
-}
-
 #define kvm_phys_to_vttbr(addr)		phys_to_ttbr(addr)
 
 static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu)
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index b2e91c187e2a..75beffe2ee8a 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -12,9 +12,6 @@
 #define USER_ASID_FLAG	(UL(1) << USER_ASID_BIT)
 #define TTBR_ASID_MASK	(UL(0xffff) << 48)
 
-#define BP_HARDEN_EL2_SLOTS 4
-#define __BP_HARDEN_HYP_VECS_SZ (BP_HARDEN_EL2_SLOTS * SZ_2K)
-
 #ifndef __ASSEMBLY__
 
 #include <linux/refcount.h>
@@ -41,32 +38,6 @@ static inline bool arm64_kernel_unmapped_at_el0(void)
 	return cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0);
 }
 
-typedef void (*bp_hardening_cb_t)(void);
-
-struct bp_hardening_data {
-	int			hyp_vectors_slot;
-	bp_hardening_cb_t	fn;
-};
-
-DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
-
-static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void)
-{
-	return this_cpu_ptr(&bp_hardening_data);
-}
-
-static inline void arm64_apply_bp_hardening(void)
-{
-	struct bp_hardening_data *d;
-
-	if (!cpus_have_const_cap(ARM64_SPECTRE_V2))
-		return;
-
-	d = arm64_get_bp_hardening_data();
-	if (d->fn)
-		d->fn();
-}
-
 extern void arm64_memblock_init(void);
 extern void paging_init(void);
 extern void bootmem_init(void);
diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
index fcdfbce302bd..4e6d90a4fbe0 100644
--- a/arch/arm64/include/asm/spectre.h
+++ b/arch/arm64/include/asm/spectre.h
@@ -9,7 +9,15 @@
 #ifndef __ASM_SPECTRE_H
 #define __ASM_SPECTRE_H
 
+#define BP_HARDEN_EL2_SLOTS 4
+#define __BP_HARDEN_HYP_VECS_SZ	((BP_HARDEN_EL2_SLOTS - 1) * SZ_2K)
+
+#ifndef __ASSEMBLY__
+
+#include <linux/percpu.h>
+
 #include <asm/cpufeature.h>
+#include <asm/virt.h>
 
 /* Watch out, ordering is important here. */
 enum mitigation_state {
@@ -20,13 +28,68 @@ enum mitigation_state {
 
 struct task_struct;
 
+/*
+ * Note: the order of this enum corresponds to __bp_harden_hyp_vecs and
+ * we rely on having the direct vectors first.
+ */
+enum arm64_hyp_spectre_vector {
+	/*
+	 * Take exceptions directly to __kvm_hyp_vector. This must be
+	 * 0 so that it used by default when mitigations are not needed.
+	 */
+	HYP_VECTOR_DIRECT,
+
+	/*
+	 * Bounce via a slot in the hypervisor text mapping of
+	 * __bp_harden_hyp_vecs, which contains an SMC call.
+	 */
+	HYP_VECTOR_SPECTRE_DIRECT,
+
+	/*
+	 * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
+	 * next to the idmap page.
+	 */
+	HYP_VECTOR_INDIRECT,
+
+	/*
+	 * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
+	 * next to the idmap page, which contains an SMC call.
+	 */
+	HYP_VECTOR_SPECTRE_INDIRECT,
+};
+
+typedef void (*bp_hardening_cb_t)(void);
+
+struct bp_hardening_data {
+	enum arm64_hyp_spectre_vector	slot;
+	bp_hardening_cb_t		fn;
+};
+
+DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
+
+static inline void arm64_apply_bp_hardening(void)
+{
+	struct bp_hardening_data *d;
+
+	if (!cpus_have_const_cap(ARM64_SPECTRE_V2))
+		return;
+
+	d = this_cpu_ptr(&bp_hardening_data);
+	if (d->fn)
+		d->fn();
+}
+
 enum mitigation_state arm64_get_spectre_v2_state(void);
 bool has_spectre_v2(const struct arm64_cpu_capabilities *cap, int scope);
 void spectre_v2_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 
+bool has_spectre_v3a(const struct arm64_cpu_capabilities *cap, int scope);
+void spectre_v3a_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
+
 enum mitigation_state arm64_get_spectre_v4_state(void);
 bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
 void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
 
+#endif	/* __ASSEMBLY__ */
 #endif	/* __ASM_SPECTRE_H */