[PATCH v2 05/14] arm64: kvm: Build hyp-entry.S separately for VHE/nVHE

From: David Brazdil
Date: Fri May 15 2020 - 06:59:11 EST

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This patch is part of a series which builds KVM's non-VHE hyp code separately
from VHE and the rest of the kernel.

hyp-entry.S contains implementation of KVM hyp vectors. This code is mostly
shared between VHE/nVHE, therefore compile it under both VHE and nVHE build
rules. nVHE-specific host HVC handler is hidden behind __KVM_NVHE_HYPERVISOR__.

Adjust code which selects which KVM hyp vecs to install to choose the correct
VHE/nVHE symbol.

Signed-off-by: David Brazdil <dbrazdil@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_asm.h | 25 ++++++++++++++++++++++++-
arch/arm64/include/asm/kvm_mmu.h | 16 ++++++++++------
arch/arm64/include/asm/mmu.h | 7 -------
arch/arm64/kernel/cpu_errata.c | 4 +++-
arch/arm64/kernel/image-vars.h | 29 ++++++++++++++++++++++++++++-
arch/arm64/kvm/hyp/hyp-entry.S | 2 ++
arch/arm64/kvm/hyp/nvhe/Makefile | 2 +-
arch/arm64/kvm/va_layout.c | 2 +-
8 files changed, 69 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 7c7eeeaab9fa..01242f54c48f 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -42,6 +42,22 @@

#include <linux/mm.h>

+/*
+ * Translate name of a symbol defined in VHE/nVHE hyp implementations
+ * to the name seen by kernel proper. All nVHE symbols are prefixed by
+ * the build system to avoid clashes with the VHE variants.
+ */
+#define __kvm_vhe_sym(sym) sym
+#define __kvm_nvhe_sym(sym) __kvm_nvhe_##sym
+
+/*
+ * Define a pair of symbols sharing the same name but one defined in
+ * VHE and the other in nVHE hyp implementations.
+ */
+#define DECLARE_KVM_HYP_SYM(sym) \
+ extern char __kvm_vhe_sym(sym)[]; \
+ extern char __kvm_nvhe_sym(sym)[]
+
/* Translate a kernel address of @sym into its equivalent linear mapping */
#define kvm_ksym_ref(sym) \
({ \
@@ -50,6 +66,8 @@
val = lm_alias(&sym); \
val; \
})
+#define kvm_ksym_ref_vhe(sym) kvm_ksym_ref(__kvm_vhe_sym(sym))
+#define kvm_ksym_ref_nvhe(sym) kvm_ksym_ref(__kvm_nvhe_sym(sym))

struct kvm;
struct kvm_vcpu;
@@ -57,7 +75,12 @@ struct kvm_vcpu;
extern char __kvm_hyp_init[];
extern char __kvm_hyp_init_end[];

-extern char __kvm_hyp_vector[];
+DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
+
+#ifdef CONFIG_KVM_INDIRECT_VECTORS
+DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs);
+extern atomic_t arm64_el2_vector_last_slot;
+#endif

extern void __kvm_flush_vm_context(void);
extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa);
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 30b0e8d6b895..871ef591042c 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -477,11 +477,15 @@ 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;
+ void *vect = kern_hyp_va(has_vhe()
+ ? kvm_ksym_ref_vhe(__kvm_hyp_vector)
+ : kvm_ksym_ref_nvhe(__kvm_hyp_vector));

if (cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR) && data->fn) {
- vect = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs));
+ vect = kern_hyp_va(has_vhe()
+ ? kvm_ksym_ref_vhe(__bp_harden_hyp_vecs)
+ : kvm_ksym_ref_nvhe(__bp_harden_hyp_vecs));
slot = data->hyp_vectors_slot;
}

@@ -510,12 +514,11 @@ static inline int kvm_map_vectors(void)
* HBP + HEL2 -> use hardened vertors and use exec mapping
*/
if (cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR)) {
- __kvm_bp_vect_base = kvm_ksym_ref(__bp_harden_hyp_vecs);
- __kvm_bp_vect_base = kern_hyp_va(__kvm_bp_vect_base);
+ __kvm_bp_vect_base = kern_hyp_va(kvm_ksym_ref_nvhe(__bp_harden_hyp_vecs));
}

if (cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS)) {
- phys_addr_t vect_pa = __pa_symbol(__bp_harden_hyp_vecs);
+ phys_addr_t vect_pa = __pa_symbol(__kvm_nvhe_sym(__bp_harden_hyp_vecs));
unsigned long size = __BP_HARDEN_HYP_VECS_SZ;

/*
@@ -534,7 +537,8 @@ static inline int kvm_map_vectors(void)
#else
static inline void *kvm_get_hyp_vector(void)
{
- return kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
+ return kern_hyp_va(has_vhe() ? kvm_ksym_ref_vhe(__kvm_hyp_vector)
+ : kvm_ksym_ref_nvhe(__kvm_hyp_vector));
}

static inline int kvm_map_vectors(void)
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 68140fdd89d6..4d913f6dd366 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -42,13 +42,6 @@ struct bp_hardening_data {
bp_hardening_cb_t fn;
};

-#if (defined(CONFIG_HARDEN_BRANCH_PREDICTOR) || \
- defined(CONFIG_HARDEN_EL2_VECTORS))
-
-extern char __bp_harden_hyp_vecs[];
-extern atomic_t arm64_el2_vector_last_slot;
-#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR || CONFIG_HARDEN_EL2_VECTORS */
-
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index a102321fc8a2..94af3af12f44 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -117,7 +117,9 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,
const char *hyp_vecs_end)
{
- void *dst = lm_alias(__bp_harden_hyp_vecs + slot * SZ_2K);
+ char *vec = has_vhe() ? __kvm_vhe_sym(__bp_harden_hyp_vecs)
+ : __kvm_nvhe_sym(__bp_harden_hyp_vecs);
+ void *dst = lm_alias(vec + slot * SZ_2K);
int i;

for (i = 0; i < SZ_2K; i += 0x80)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 13850134fc28..dc9c14d91d39 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -54,13 +54,40 @@ __efistub__ctype = _ctype;
#ifdef CONFIG_KVM

/*
- * KVM nVHE code has its own symbol namespace prefixed by __hyp_text_, to
+ * KVM nVHE code has its own symbol namespace prefixed by __kvm_nvhe_, to
* isolate it from the kernel proper. The following symbols are legally
* accessed by it, therefore provide aliases to make them linkable.
* Do not include symbols which may not be safely accessed under hypervisor
* memory mappings.
*/

+__kvm_nvhe___guest_exit = __guest_exit;
+__kvm_nvhe___kvm_enable_ssbs = __kvm_enable_ssbs;
+__kvm_nvhe___kvm_flush_vm_context = __kvm_flush_vm_context;
+__kvm_nvhe___kvm_get_mdcr_el2 = __kvm_get_mdcr_el2;
+__kvm_nvhe___kvm_handle_stub_hvc = __kvm_handle_stub_hvc;
+__kvm_nvhe___kvm_timer_set_cntvoff = __kvm_timer_set_cntvoff;
+__kvm_nvhe___kvm_tlb_flush_local_vmid = __kvm_tlb_flush_local_vmid;
+__kvm_nvhe___kvm_tlb_flush_vmid = __kvm_tlb_flush_vmid;
+__kvm_nvhe___kvm_tlb_flush_vmid_ipa = __kvm_tlb_flush_vmid_ipa;
+__kvm_nvhe___kvm_vcpu_run_nvhe = __kvm_vcpu_run_nvhe;
+__kvm_nvhe___vgic_v3_get_ich_vtr_el2 = __vgic_v3_get_ich_vtr_el2;
+__kvm_nvhe___vgic_v3_init_lrs = __vgic_v3_init_lrs;
+__kvm_nvhe___vgic_v3_read_vmcr = __vgic_v3_read_vmcr;
+__kvm_nvhe___vgic_v3_restore_aprs = __vgic_v3_restore_aprs;
+__kvm_nvhe___vgic_v3_save_aprs = __vgic_v3_save_aprs;
+__kvm_nvhe___vgic_v3_write_vmcr = __vgic_v3_write_vmcr;
+__kvm_nvhe_abort_guest_exit_end = abort_guest_exit_end;
+__kvm_nvhe_abort_guest_exit_start = abort_guest_exit_start;
+__kvm_nvhe_arm64_enable_wa2_handling = arm64_enable_wa2_handling;
+__kvm_nvhe_arm64_ssbd_callback_required = arm64_ssbd_callback_required;
+__kvm_nvhe_hyp_panic = hyp_panic;
+__kvm_nvhe_kimage_voffset = kimage_voffset;
+__kvm_nvhe_kvm_host_data = kvm_host_data;
+__kvm_nvhe_kvm_patch_vector_branch = kvm_patch_vector_branch;
+__kvm_nvhe_kvm_update_va_mask = kvm_update_va_mask;
+__kvm_nvhe_panic = panic;
+
#endif /* CONFIG_KVM */

#endif /* __ARM64_KERNEL_IMAGE_VARS_H */
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index ab14de8d0131..81c65fa65183 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -27,6 +27,7 @@ el1_sync: // Guest trapped into EL2
ccmp x0, #ESR_ELx_EC_HVC32, #4, ne
b.ne el1_trap

+#ifdef __KVM_NVHE_HYPERVISOR__
mrs x1, vttbr_el2 // If vttbr is valid, the guest
cbnz x1, el1_hvc_guest // called HVC

@@ -86,6 +87,7 @@ el1_host_invalid_hvc:
mov x0, -ENOSYS
eret
sb
+#endif /* __KVM_NVHE_HYPERVISOR__ */

el1_hvc_guest:
/*
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 7d64235dba62..c68801e24950 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -7,7 +7,7 @@ asflags-y := -D__KVM_NVHE_HYPERVISOR__
ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -fno-stack-protector \
-DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN)

-obj-y :=
+obj-y := ../hyp-entry.o

obj-y := $(patsubst %.o,%.hyp.o,$(obj-y))
extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y))
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index a4f48c1ac28c..157d106235f7 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -150,7 +150,7 @@ void kvm_patch_vector_branch(struct alt_instr *alt,
/*
* Compute HYP VA by using the same computation as kern_hyp_va()
*/
- addr = (uintptr_t)kvm_ksym_ref(__kvm_hyp_vector);
+ addr = (uintptr_t)kvm_ksym_ref_nvhe(__kvm_hyp_vector);
addr &= va_mask;
addr |= tag_val << tag_lsb;

--
2.26.2

Next message: David Brazdil: "[PATCH v2 04/14] arm64: kvm: Add build rules for separate nVHE object files"
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