[Xen-devel] [RFC 01/16] 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 51d2e42c77..9251ae50b8 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -682,8 +682,7 @@ 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 8016cf306f..975c8ff097 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -840,6 +840,24 @@ void abort_guest_exit_end(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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