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Subject[PATCH v3 04/11] kvm: arm64: Remove __hyp_this_cpu_read
Date
this_cpu_ptr is meant for use in kernel proper because it selects between
TPIDR_EL1/2 based on nVHE/VHE. __hyp_this_cpu_ptr was used in hyp to always
select TPIDR_EL2. Unify all users behind this_cpu_ptr and friends by
selecting _EL2 register under __KVM_VHE/NVHE_HYPERVISOR__.

Under CONFIG_DEBUG_PREEMPT, the kernel helpers perform a preemption check
which is omitted by the hyp helpers. Preserve the behavior for nVHE by
overriding the corresponding macros under __KVM_NVHE_HYPERVISOR__. Extend
the checks into VHE hyp code.

Acked-by: Andrew Scull <ascull@google.com>
Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/include/asm/kvm_asm.h | 20 --------------
arch/arm64/include/asm/percpu.h | 33 +++++++++++++++++++++--
arch/arm64/kvm/hyp/include/hyp/debug-sr.h | 4 +--
arch/arm64/kvm/hyp/include/hyp/switch.h | 8 +++---
arch/arm64/kvm/hyp/nvhe/switch.c | 2 +-
arch/arm64/kvm/hyp/vhe/switch.c | 2 +-
arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 4 +--
7 files changed, 41 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index c085032e2e3e..c196eec25498 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -143,26 +143,6 @@ extern char __smccc_workaround_1_smc[__SMCCC_WORKAROUND_1_SMC_SZ];
addr; \
})

-/*
- * Home-grown __this_cpu_{ptr,read} variants that always work at HYP,
- * provided that sym is really a *symbol* and not a pointer obtained from
- * a data structure. As for SHIFT_PERCPU_PTR(), the creative casting keeps
- * sparse quiet.
- */
-#define __hyp_this_cpu_ptr(sym) \
- ({ \
- void *__ptr; \
- __verify_pcpu_ptr(&sym); \
- __ptr = hyp_symbol_addr(sym); \
- __ptr += read_sysreg(tpidr_el2); \
- (typeof(sym) __kernel __force *)__ptr; \
- })
-
-#define __hyp_this_cpu_read(sym) \
- ({ \
- *__hyp_this_cpu_ptr(sym); \
- })
-
#define __KVM_EXTABLE(from, to) \
" .pushsection __kvm_ex_table, \"a\"\n" \
" .align 3\n" \
diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h
index 0b6409b89e5e..36f304401c38 100644
--- a/arch/arm64/include/asm/percpu.h
+++ b/arch/arm64/include/asm/percpu.h
@@ -19,7 +19,21 @@ static inline void set_my_cpu_offset(unsigned long off)
:: "r" (off) : "memory");
}

-static inline unsigned long __my_cpu_offset(void)
+static inline unsigned long __hyp_my_cpu_offset(void)
+{
+ unsigned long off;
+
+ /*
+ * We want to allow caching the value, so avoid using volatile and
+ * instead use a fake stack read to hazard against barrier().
+ */
+ asm("mrs %0, tpidr_el2" : "=r" (off) :
+ "Q" (*(const unsigned long *)current_stack_pointer));
+
+ return off;
+}
+
+static inline unsigned long __kern_my_cpu_offset(void)
{
unsigned long off;

@@ -35,7 +49,12 @@ static inline unsigned long __my_cpu_offset(void)

return off;
}
-#define __my_cpu_offset __my_cpu_offset()
+
+#if defined(__KVM_NVHE_HYPERVISOR__) || defined(__KVM_VHE_HYPERVISOR__)
+#define __my_cpu_offset __hyp_my_cpu_offset()
+#else
+#define __my_cpu_offset __kern_my_cpu_offset()
+#endif

#define PERCPU_RW_OPS(sz) \
static inline unsigned long __percpu_read_##sz(void *ptr) \
@@ -227,4 +246,14 @@ PERCPU_RET_OP(add, add, ldadd)

#include <asm-generic/percpu.h>

+/* Redefine macros for nVHE hyp under DEBUG_PREEMPT to avoid its dependencies. */
+#if defined(__KVM_NVHE_HYPERVISOR__) && defined(CONFIG_DEBUG_PREEMPT)
+#undef this_cpu_ptr
+#define this_cpu_ptr raw_cpu_ptr
+#undef __this_cpu_read
+#define __this_cpu_read raw_cpu_read
+#undef __this_cpu_write
+#define __this_cpu_write raw_cpu_write
+#endif
+
#endif /* __ASM_PERCPU_H */
diff --git a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
index 5e28ea6aa097..4ebe9f558f3a 100644
--- a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
@@ -135,7 +135,7 @@ static inline void __debug_switch_to_guest_common(struct kvm_vcpu *vcpu)
if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
return;

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
guest_ctxt = &vcpu->arch.ctxt;
host_dbg = &vcpu->arch.host_debug_state.regs;
guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
@@ -154,7 +154,7 @@ static inline void __debug_switch_to_host_common(struct kvm_vcpu *vcpu)
if (!(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY))
return;

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
guest_ctxt = &vcpu->arch.ctxt;
host_dbg = &vcpu->arch.host_debug_state.regs;
guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 5b6b8fa00f0a..f150407fa798 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -386,7 +386,7 @@ static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
!esr_is_ptrauth_trap(kvm_vcpu_get_esr(vcpu)))
return false;

- ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
__ptrauth_save_key(ctxt, APIA);
__ptrauth_save_key(ctxt, APIB);
__ptrauth_save_key(ctxt, APDA);
@@ -495,7 +495,7 @@ static inline void __set_guest_arch_workaround_state(struct kvm_vcpu *vcpu)
* guest wants it disabled, so be it...
*/
if (__needs_ssbd_off(vcpu) &&
- __hyp_this_cpu_read(arm64_ssbd_callback_required))
+ __this_cpu_read(arm64_ssbd_callback_required))
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 0, NULL);
#endif
}
@@ -507,7 +507,7 @@ static inline void __set_host_arch_workaround_state(struct kvm_vcpu *vcpu)
* If the guest has disabled the workaround, bring it back on.
*/
if (__needs_ssbd_off(vcpu) &&
- __hyp_this_cpu_read(arm64_ssbd_callback_required))
+ __this_cpu_read(arm64_ssbd_callback_required))
arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 1, NULL);
#endif
}
@@ -521,7 +521,7 @@ static inline void __kvm_unexpected_el2_exception(void)

entry = hyp_symbol_addr(__start___kvm_ex_table);
end = hyp_symbol_addr(__stop___kvm_ex_table);
- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;

while (entry < end) {
addr = (unsigned long)&entry->insn + entry->insn;
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 0970442d2dbc..cc4f8e790fb3 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -175,7 +175,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)

vcpu = kern_hyp_va(vcpu);

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index c1da4f86ccac..575e8054f116 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -108,7 +108,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
struct kvm_cpu_context *guest_ctxt;
u64 exit_code;

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
host_ctxt->__hyp_running_vcpu = vcpu;
guest_ctxt = &vcpu->arch.ctxt;

diff --git a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
index 996471e4c138..2a0b8c88d74f 100644
--- a/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/vhe/sysreg-sr.c
@@ -66,7 +66,7 @@ void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu)
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
struct kvm_cpu_context *host_ctxt;

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
__sysreg_save_user_state(host_ctxt);

/*
@@ -100,7 +100,7 @@ void kvm_vcpu_put_sysregs_vhe(struct kvm_vcpu *vcpu)
struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
struct kvm_cpu_context *host_ctxt;

- host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+ host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
deactivate_traps_vhe_put();

__sysreg_save_el1_state(guest_ctxt);
--
2.28.0.618.gf4bc123cb7-goog
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