[PATCH 4.9 62/66] arm64: KVM: Add HYP per-cpu accessors

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 85478bab409171de501b719971fd25a3d5d639f9 upstream.

As we're going to require to access per-cpu variables at EL2,
let's craft the minimum set of accessors required to implement
reading a per-cpu variable, relying on tpidr_el2 to contain the
per-cpu offset.

Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxx>
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_asm.h |   27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -66,14 +66,37 @@ extern u32 __kvm_get_mdcr_el2(void);
 
 extern u32 __init_stage2_translation(void);
 
+/* Home-grown __this_cpu_{ptr,read} variants that always work at HYP */
+#define __hyp_this_cpu_ptr(sym)						\
+	({								\
+		void *__ptr = hyp_symbol_addr(sym);			\
+		__ptr += read_sysreg(tpidr_el2);			\
+		(typeof(&sym))__ptr;					\
+	 })
+
+#define __hyp_this_cpu_read(sym)					\
+	({								\
+		*__hyp_this_cpu_ptr(sym);				\
+	 })
+
 #else /* __ASSEMBLY__ */
 
-.macro get_host_ctxt reg, tmp
-	adr_l	\reg, kvm_host_cpu_state
+.macro hyp_adr_this_cpu reg, sym, tmp
+	adr_l	\reg, \sym
 	mrs	\tmp, tpidr_el2
 	add	\reg, \reg, \tmp
 .endm
 
+.macro hyp_ldr_this_cpu reg, sym, tmp
+	adr_l	\reg, \sym
+	mrs	\tmp, tpidr_el2
+	ldr	\reg,  [\reg, \tmp]
+.endm
+
+.macro get_host_ctxt reg, tmp
+	hyp_adr_this_cpu \reg, kvm_host_cpu_state, \tmp
+.endm
+
 .macro get_vcpu_ptr vcpu, ctxt
 	get_host_ctxt \ctxt, \vcpu
 	ldr	\vcpu, [\ctxt, #HOST_CONTEXT_VCPU]