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Subject[PATCH 4.17 095/101] arm64: KVM: Add HYP per-cpu accessors
Date
4.17-stable review patch.  If anyone has any objections, please let me know.

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

From: Marc Zyngier <marc.zyngier@arm.com>

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@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -71,14 +71,37 @@ 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]

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