[XEN PATCH v3 02/16] x86/altp2m: check if altp2m active when giving away p2midx

[Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>]

Explicitly check whether altp2m is on for domain when getting altp2m index.

The puspose of that is later to be able to disable altp2m support and
exclude its code from the build completely, when not supported by target
platform (as of now it's implemented for Intel EPT only).

Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>
CC: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
---
changes in v3:
 - move altp2m_active() check inside altp2m_vcpu_idx()
 - drop changes to monitor.c
 - changed patch description
changes in v2:
 - patch description changed, removed VMX mentioning
 - guard by altp2m_active() instead of hvm_altp2m_supported()
---
 xen/arch/x86/include/asm/altp2m.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/include/asm/altp2m.h 
b/xen/arch/x86/include/asm/altp2m.h
index e5e59cbd68..2d36c5aa9b 100644
--- a/xen/arch/x86/include/asm/altp2m.h
+++ b/xen/arch/x86/include/asm/altp2m.h
@@ -26,10 +26,6 @@ void altp2m_vcpu_destroy(struct vcpu *v);
 int altp2m_vcpu_enable_ve(struct vcpu *v, gfn_t gfn);
 void altp2m_vcpu_disable_ve(struct vcpu *v);
 
-static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v)
-{
-    return vcpu_altp2m(v).p2midx;
-}
 #else
 
 static inline bool altp2m_active(const struct domain *d)
@@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d)
 }
 
 /* Only declaration is needed. DCE will optimise it out when linking. */
-uint16_t altp2m_vcpu_idx(const struct vcpu *v);
 void altp2m_vcpu_disable_ve(struct vcpu *v);
 
 #endif
 
+static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v)
+{
+    return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0;
+}
+
 #endif /* __ASM_X86_ALTP2M_H */
-- 
2.25.1