[RFC PATCH v6 25/43] arm/altp2m: Add altp2m index to arch_vcpu

[Rose Spangler <Rose.Spangler@xxxxxxxxxxxxxx>]

This commit adds ap2m_idx to the VCPU struct on ARM. This makes it possible
to track the current altp2m view being used by a VCPU.

This is commit 2/4 of the altp2m_{get,set}_altp2m phase.

Signed-off-by: Rose Spangler <Rose.Spangler@xxxxxxxxxxxxxx>
Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
v6: This patch was originally part of the "arm/p2m: Add
    HVMOP_altp2m_set_domain_state" patch from the v4/v5 patch series.
    It has been extracted into its own commit to make the patch series
    easier to follow. If it would be preferred, this commit can be squashed
    into another commit.

    Added support for the CONFIG_ALTP2M option.
---
 xen/arch/arm/include/asm/altp2m.h | 4 +---
 xen/arch/arm/include/asm/domain.h | 5 +++++
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/include/asm/altp2m.h 
b/xen/arch/arm/include/asm/altp2m.h
index 5a217f48b103..bc695018e62c 100644
--- a/xen/arch/arm/include/asm/altp2m.h
+++ b/xen/arch/arm/include/asm/altp2m.h
@@ -26,9 +26,7 @@ static inline bool altp2m_supported(void)
 /* Alternate p2m VCPU */
 static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v)
 {
-    /* Not implemented yet */
-    BUG();
-    return 0;
+    return v->arch.ap2m_idx;
 }
 
 #else /* CONFIG_ALTP2M */
diff --git a/xen/arch/arm/include/asm/domain.h 
b/xen/arch/arm/include/asm/domain.h
index 9e69d62086cd..4d497a21b648 100644
--- a/xen/arch/arm/include/asm/domain.h
+++ b/xen/arch/arm/include/asm/domain.h
@@ -249,6 +249,11 @@ struct arch_vcpu
     struct vtimer virt_timer;
     bool   vtimer_initialized;
 
+#if CONFIG_ALTP2M
+    /* Alternate p2m index */
+    uint16_t ap2m_idx;
+#endif
+
     /*
      * The full P2M may require some cleaning (e.g when emulation
      * set/way). As the action can take a long time, it requires
-- 
2.34.1