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Subject[PATCH v4 07/10] kvm: arm64: Duplicate arm64_ssbd_callback_required for nVHE hyp
Date
Hyp keeps track of which cores require SSBD callback by accessing a
kernel-proper global variable. Create an nVHE symbol of the same name
and copy the value from kernel proper to nVHE as KVM is being enabled
on a core.

Done in preparation for separating percpu memory owned by kernel
proper and nVHE.

Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/include/asm/kvm_mmu.h | 14 +++++++++++++-
arch/arm64/kernel/image-vars.h | 1 -
arch/arm64/kvm/arm.c | 3 +++
arch/arm64/kvm/hyp/nvhe/switch.c | 3 +++
4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 189839c3706a..e134c2ba2c5d 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -529,6 +529,7 @@ static inline int kvm_map_vectors(void)

#ifdef CONFIG_ARM64_SSBD
DECLARE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
+DECLARE_KVM_NVHE_PER_CPU(u64, arm64_ssbd_callback_required);

static inline int hyp_map_aux_data(void)
{
@@ -537,18 +538,29 @@ static inline int hyp_map_aux_data(void)
for_each_possible_cpu(cpu) {
u64 *ptr;

- ptr = per_cpu_ptr(&arm64_ssbd_callback_required, cpu);
+ ptr = per_cpu_ptr_nvhe_sym(arm64_ssbd_callback_required, cpu);
err = create_hyp_mappings(ptr, ptr + 1, PAGE_HYP);
if (err)
return err;
}
return 0;
}
+
+static inline void hyp_init_aux_data(void)
+{
+ u64 *ptr;
+
+ /* Copy arm64_ssbd_callback_required value from kernel to hyp. */
+ ptr = this_cpu_ptr_nvhe_sym(arm64_ssbd_callback_required);
+ *ptr = __this_cpu_read(arm64_ssbd_callback_required);
+}
#else
static inline int hyp_map_aux_data(void)
{
return 0;
}
+
+static inline void hyp_init_aux_data(void) {}
#endif

#define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 76da2ad1010c..59d12a0b4622 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -67,7 +67,6 @@ KVM_NVHE_ALIAS(kvm_patch_vector_branch);
KVM_NVHE_ALIAS(kvm_update_va_mask);

/* Global kernel state accessed by nVHE hyp code. */
-KVM_NVHE_ALIAS(arm64_ssbd_callback_required);
KVM_NVHE_ALIAS(kvm_host_data);
KVM_NVHE_ALIAS(kvm_vgic_global_state);

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index b588c3b5c2f0..76be11d31e5d 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1298,6 +1298,9 @@ static void cpu_init_hyp_mode(void)
arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) {
kvm_call_hyp_nvhe(__kvm_enable_ssbs);
}
+
+ /* Copy information whether SSBD callback is required to hyp. */
+ hyp_init_aux_data();
}

static void cpu_hyp_reset(void)
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index cc4f8e790fb3..4662df6330d7 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -27,6 +27,9 @@
#include <asm/processor.h>
#include <asm/thread_info.h>

+/* Non-VHE copy of the kernel symbol. */
+DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
+
static void __activate_traps(struct kvm_vcpu *vcpu)
{
u64 val;
--
2.28.0.681.g6f77f65b4e-goog
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