[Xen-devel] [PATCH for-4.12 v2 01/17] xen/arm: Introduce helpers to clear/flags flags in HCR_EL2

[Julien Grall <julien.grall@xxxxxxx>]

A couple of places in the code will need to clear/set flags in HCR_EL2
for a given vCPU and then replicate into the hardware. Introduce
helpers and replace open-coded version.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

---

The patch was previously sent separately and reviewed by Stefano.

I haven't find a good place for those new helpers so stick to
processor.h at the moment. This require to use macro rather than inline
helpers given that processor.h is usually the root of all headers.
---
 xen/arch/arm/traps.c            |  3 +--
 xen/include/asm-arm/processor.h | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 88ffeeb480..c05a8ad25c 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -681,8 +681,7 @@ static void inject_vabt_exception(struct cpu_user_regs 
*regs)
         break;
     }
 
-    current->arch.hcr_el2 |= HCR_VA;
-    WRITE_SYSREG(current->arch.hcr_el2, HCR_EL2);
+    vcpu_hcr_set_flags(current, HCR_VA);
 }
 
 /*
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 72ddc42778..cb781751a6 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -490,6 +490,24 @@ register_t get_default_hcr_flags(void);
                                  : : : "memory");                 \
     } while (0)
 
+/*
+ * Clear/Set flags in HCR_EL2 for a given vCPU. It only supports the current
+ * vCPU for now.
+ */
+#define vcpu_hcr_clear_flags(v, flags)              \
+    do {                                            \
+        ASSERT((v) == current);                     \
+        (v)->arch.hcr_el2 &= ~(flags);              \
+        WRITE_SYSREG((v)->arch.hcr_el2, HCR_EL2);   \
+    } while (0)
+
+#define vcpu_hcr_set_flags(v, flags)                \
+    do {                                            \
+        ASSERT((v) == current);                     \
+        (v)->arch.hcr_el2 |= (flags);               \
+        WRITE_SYSREG((v)->arch.hcr_el2, HCR_EL2);   \
+    } while (0)
+
 #endif /* __ASSEMBLY__ */
 #endif /* __ASM_ARM_PROCESSOR_H */
 /*
-- 
2.11.0


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