[XEN PATCH v2 06/15] x86/p2m: guard altp2m code with CONFIG_ALTP2M option

[Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>]

Instead of using generic CONFIG_HVM option switch to a bit more specific
CONFIG_ALTP2M option for altp2m support. Also guard altp2m routines, so that
they can be disabled completely in the build -- when target platform does not
actually support altp2m (AMD-V & ARM as of now).

Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>
CC: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
changes in v2:
 - use separate CONFIG_ALTP2M option instead of CONFIG_VMX
---
 xen/arch/x86/include/asm/altp2m.h  |  5 ++++-
 xen/arch/x86/include/asm/hvm/hvm.h |  2 +-
 xen/arch/x86/include/asm/p2m.h     | 17 ++++++++++++++++-
 xen/arch/x86/mm/Makefile           |  2 +-
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/include/asm/altp2m.h 
b/xen/arch/x86/include/asm/altp2m.h
index e5e59cbd68..092b13e231 100644
--- a/xen/arch/x86/include/asm/altp2m.h
+++ b/xen/arch/x86/include/asm/altp2m.h
@@ -7,7 +7,7 @@
 #ifndef __ASM_X86_ALTP2M_H
 #define __ASM_X86_ALTP2M_H
 
-#ifdef CONFIG_HVM
+#ifdef CONFIG_ALTP2M
 
 #include <xen/types.h>
 #include <xen/sched.h>         /* for struct vcpu, struct domain */
@@ -38,7 +38,10 @@ static inline bool altp2m_active(const struct domain *d)
 }
 
 /* Only declaration is needed. DCE will optimise it out when linking. */
+void altp2m_vcpu_initialise(struct vcpu *v);
+void altp2m_vcpu_destroy(struct vcpu *v);
 uint16_t altp2m_vcpu_idx(const struct vcpu *v);
+int altp2m_vcpu_enable_ve(struct vcpu *v, gfn_t gfn);
 void altp2m_vcpu_disable_ve(struct vcpu *v);
 
 #endif
diff --git a/xen/arch/x86/include/asm/hvm/hvm.h 
b/xen/arch/x86/include/asm/hvm/hvm.h
index 0c9e6f1564..4f03dd7af8 100644
--- a/xen/arch/x86/include/asm/hvm/hvm.h
+++ b/xen/arch/x86/include/asm/hvm/hvm.h
@@ -670,7 +670,7 @@ static inline bool hvm_hap_supported(void)
 /* returns true if hardware supports alternate p2m's */
 static inline bool hvm_altp2m_supported(void)
 {
-    return hvm_funcs.caps.altp2m;
+    return IS_ENABLED(CONFIG_ALTP2M) && hvm_funcs.caps.altp2m;
 }
 
 /* Returns true if we have the minimum hardware requirements for nested virt */
diff --git a/xen/arch/x86/include/asm/p2m.h b/xen/arch/x86/include/asm/p2m.h
index 111badf89a..855e69d24a 100644
--- a/xen/arch/x86/include/asm/p2m.h
+++ b/xen/arch/x86/include/asm/p2m.h
@@ -581,9 +581,9 @@ static inline gfn_t mfn_to_gfn(const struct domain *d, 
mfn_t mfn)
         return _gfn(mfn_x(mfn));
 }
 
-#ifdef CONFIG_HVM
 #define AP2MGET_prepopulate true
 #define AP2MGET_query false
+#ifdef CONFIG_ALTP2M
 
 /*
  * Looks up altp2m entry. If the entry is not found it looks up the entry in
@@ -593,6 +593,15 @@ static inline gfn_t mfn_to_gfn(const struct domain *d, 
mfn_t mfn)
 int altp2m_get_effective_entry(struct p2m_domain *ap2m, gfn_t gfn, mfn_t *mfn,
                                p2m_type_t *t, p2m_access_t *a,
                                bool prepopulate);
+#else
+static inline int altp2m_get_effective_entry(struct p2m_domain *ap2m,
+                                             gfn_t gfn, mfn_t *mfn,
+                                             p2m_type_t *t, p2m_access_t *a,
+                                             bool prepopulate)
+{
+    ASSERT_UNREACHABLE();
+    return -EOPNOTSUPP;
+}
 #endif
 
 /* Init the datastructures for later use by the p2m code */
@@ -909,8 +918,14 @@ static inline bool p2m_set_altp2m(struct vcpu *v, unsigned 
int idx)
 /* Switch alternate p2m for a single vcpu */
 bool p2m_switch_vcpu_altp2m_by_id(struct vcpu *v, unsigned int idx);
 
+#ifdef CONFIG_ALTP2M
 /* Check to see if vcpu should be switched to a different p2m. */
 void p2m_altp2m_check(struct vcpu *v, uint16_t idx);
+#else
+static inline void p2m_altp2m_check(struct vcpu *v, uint16_t idx)
+{
+}
+#endif
 
 /* Flush all the alternate p2m's for a domain */
 void p2m_flush_altp2m(struct domain *d);
diff --git a/xen/arch/x86/mm/Makefile b/xen/arch/x86/mm/Makefile
index 0128ca7ab6..d7d57b8190 100644
--- a/xen/arch/x86/mm/Makefile
+++ b/xen/arch/x86/mm/Makefile
@@ -1,7 +1,7 @@
 obj-y += shadow/
 obj-$(CONFIG_HVM) += hap/
 
-obj-$(CONFIG_HVM) += altp2m.o
+obj-$(CONFIG_ALTP2M) += altp2m.o
 obj-$(CONFIG_HVM) += guest_walk_2.o guest_walk_3.o guest_walk_4.o
 obj-$(CONFIG_SHADOW_PAGING) += guest_walk_4.o
 obj-$(CONFIG_MEM_ACCESS) += mem_access.o
-- 
2.25.1