[PATCH v4 12/30] x86/domain_page: move struct mapcache_vcpu to struct arch_vcpu

[George Dunlap <gwd@xxxxxxxxxxxxxx>]

From: Roger Pau Monné <roger.pau@xxxxxxxxxx>

struct mapcache_vcpu, the per-vCPU part of the mapcache (the maphash
and the vCPU's shadow of the domain's TLB epoch), lives in struct
pv_vcpu, as only PV vCPUs have a mapcache.  In preparation for
implementing mapcaches for HVM domains, move it to struct arch_vcpu:
v->arch.pv.mapcache becomes v->arch.mapcache.

struct pv_vcpu shrinks from 512 to 376 bytes, and struct vcpu grows
from 2880 to 3008 bytes (x86_64, debug build), within its page: from
here on HVM vCPUs carry the 136-byte struct mapcache_vcpu too, ahead of
its use by those of vCPU-PT domains.

No functional change.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Assisted-by: Claude Code:claude-fable-5, Claude Code:claude-opus-4-8, Claude 
Code:claude-opus-5-5
Signed-off-by: George Dunlap <gwd@xxxxxxxxxxxxxx>
Reviewed-by: Roger Pau Monné <roger@xxxxxxxxxxxxxx>
---
Changes in v3:
- New in this version, split out of "x86/hvm: introduce per-vCPU
  mapcache for vCPU-PT domains" for review.
---
 xen/arch/x86/domain_page.c        | 6 +++---
 xen/arch/x86/include/asm/domain.h | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/domain_page.c b/xen/arch/x86/domain_page.c
index e4ea7a254f..205d7b832a 100644
--- a/xen/arch/x86/domain_page.c
+++ b/xen/arch/x86/domain_page.c
@@ -127,7 +127,7 @@ void *map_domain_page(mfn_t mfn)
         return mfn_to_virt(mfn_x(mfn));
 
     cache = vcpu_mapcache(v, &dcache);
-    vcache = &v->arch.pv.mapcache;
+    vcache = &v->arch.mapcache;
     if ( !cache->inuse )
         return mfn_to_virt(mfn_x(mfn));
 
@@ -224,7 +224,7 @@ void unmap_domain_page(const void *ptr)
 
     idx = PFN_DOWN(va - MAPCACHE_VIRT_START);
     mfn = l1e_get_pfn(MAPCACHE_L1ENT(idx));
-    hashent = &v->arch.pv.mapcache.hash[MAPHASH_HASHFN(mfn)];
+    hashent = &v->arch.mapcache.hash[MAPHASH_HASHFN(mfn)];
 
     local_irq_save(flags);
 
@@ -324,7 +324,7 @@ int mapcache_vcpu_init(struct vcpu *v)
     BUILD_BUG_ON(MAPHASHENT_NOTINUSE < MAPCACHE_ENTRIES);
     for ( i = 0; i < MAPHASH_ENTRIES; i++ )
     {
-        struct vcpu_maphash_entry *hashent = &v->arch.pv.mapcache.hash[i];
+        struct vcpu_maphash_entry *hashent = &v->arch.mapcache.hash[i];
 
         hashent->mfn = ~0UL; /* never valid to map */
         hashent->idx = MAPHASHENT_NOTINUSE;
diff --git a/xen/arch/x86/include/asm/domain.h 
b/xen/arch/x86/include/asm/domain.h
index 542c6b5eca..45d308407e 100644
--- a/xen/arch/x86/include/asm/domain.h
+++ b/xen/arch/x86/include/asm/domain.h
@@ -545,9 +545,6 @@ struct arch_domain
 
 struct pv_vcpu
 {
-    /* map_domain_page() mapping cache. */
-    struct mapcache_vcpu mapcache;
-
     unsigned int vgc_flags;
 
     struct trap_info *trap_ctxt;
@@ -643,6 +640,9 @@ struct arch_vcpu
 #define async_exception_state(t) async_exception_state[(t)-1]
     uint8_t async_exception_mask;
 
+    /* map_domain_page() mapping cache. */
+    struct mapcache_vcpu mapcache;
+
     /* Virtual Machine Extensions */
     union {
         struct pv_vcpu pv;
-- 
2.55.0