[PATCH v3 05/15] arm64: kvm: Build hyp-entry.S separately for VHE/nVHE

David Brazdil
2020-06-18T12:28:12Z

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@google.com>
---
arch/arm64/include/asm/kvm_asm.h | 7 ++++++-
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 | 12 ++++++++++++
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, 35 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 6a682d66a640..2baa69324cc9 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -76,7 +76,12 @@ 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 b12bfc1f051a..5bfc7ee61997 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -461,11 +461,15 @@ 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(__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(__bp_harden_hyp_vecs)
+ : kvm_ksym_ref_nvhe(__bp_harden_hyp_vecs));
slot = data->hyp_vectors_slot;
}

@@ -494,12 +498,11 @@ 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;

/*
@@ -518,7 +521,8 @@ 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(__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 ad06d6802d2e..318b76a62c56 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() ? __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 89affa38b143..dc7ee85531f5 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -61,9 +61,11 @@ __efistub__ctype = _ctype;
* 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;
@@ -75,6 +77,16 @@ __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 */

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index d362fad97cc8..7e3c72fa634f 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -40,6 +40,7 @@ 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

@@ -74,6 +75,7 @@ el1_sync: // Guest trapped into EL2

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;

--
2.27.0