[xen master] x86/shadow: drop is_hvm_...() where easily possible

[patchbot@xxxxxxx]

commit 227b86fee0c96eabe742d904e47f368b52cd09e6
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Feb 24 09:15:34 2026 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Feb 24 10:29:47 2026 +0100

    x86/shadow: drop is_hvm_...() where easily possible
    
    These emulation related functions are involved in HVM handling only, and
    in some cases they even invoke such checks after having already done
    things which are valid for HVM domains only. OOS active also implies HVM.
    In sh_remove_all_mappings() one of the two checks is redundant with an
    earlier paging_mode_external() one (the other, however, needs to stay).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/mm/shadow/common.c |  2 +-
 xen/arch/x86/mm/shadow/hvm.c    | 20 +-------------------
 xen/arch/x86/mm/shadow/multi.c  |  2 +-
 xen/arch/x86/mm/shadow/oos.c    |  1 -
 4 files changed, 3 insertions(+), 22 deletions(-)

diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 6d44d9ad1d..c89ab8e063 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -1512,7 +1512,7 @@ int sh_remove_all_mappings(struct domain *d, mfn_t gmfn, 
gfn_t gfn)
                && (page->count_info & PGC_count_mask) <= 3
                && ((page->u.inuse.type_info & PGT_count_mask)
                    == (is_special_page(page) ||
-                       (is_hvm_domain(d) && is_ioreq_server_page(d, page))))) )
+                       is_ioreq_server_page(d, page)))) )
             printk(XENLOG_G_ERR "can't find all mappings of mfn %"PRI_mfn
                    " (gfn %"PRI_gfn"): c=%lx t=%lx s=%d i=%d\n",
                    mfn_x(gmfn), gfn_x(gfn),
diff --git a/xen/arch/x86/mm/shadow/hvm.c b/xen/arch/x86/mm/shadow/hvm.c
index 7b3b58119c..a7db8addc0 100644
--- a/xen/arch/x86/mm/shadow/hvm.c
+++ b/xen/arch/x86/mm/shadow/hvm.c
@@ -192,10 +192,6 @@ hvm_emulate_write(enum x86_segment seg,
     if ( rc || !bytes )
         return rc;
 
-    /* Unaligned writes are only acceptable on HVM */
-    if ( (addr & (bytes - 1)) && !is_hvm_vcpu(v)  )
-        return X86EMUL_UNHANDLEABLE;
-
     ptr = sh_emulate_map_dest(v, addr, bytes, sh_ctxt);
     if ( IS_ERR(ptr) )
         return ~PTR_ERR(ptr);
@@ -248,10 +244,6 @@ hvm_emulate_cmpxchg(enum x86_segment seg,
     if ( rc )
         return rc;
 
-    /* Unaligned writes are only acceptable on HVM */
-    if ( (addr & (bytes - 1)) && !is_hvm_vcpu(v)  )
-        return X86EMUL_UNHANDLEABLE;
-
     ptr = sh_emulate_map_dest(v, addr, bytes, sh_ctxt);
     if ( IS_ERR(ptr) )
         return ~PTR_ERR(ptr);
@@ -466,8 +458,7 @@ static void *sh_emulate_map_dest(struct vcpu *v, unsigned 
long vaddr,
 
 #ifndef NDEBUG
     /* We don't emulate user-mode writes to page tables. */
-    if ( is_hvm_domain(d) ? hvm_get_cpl(v) == 3
-                          : !guest_kernel_mode(v, guest_cpu_user_regs()) )
+    if ( hvm_get_cpl(v) == 3 )
     {
         gdprintk(XENLOG_DEBUG, "User-mode write to pagetable reached "
                  "emulate_map_dest(). This should never happen!\n");
@@ -496,15 +487,6 @@ static void *sh_emulate_map_dest(struct vcpu *v, unsigned 
long vaddr,
         sh_ctxt->mfn[1] = INVALID_MFN;
         map = map_domain_page(sh_ctxt->mfn[0]) + (vaddr & ~PAGE_MASK);
     }
-    else if ( !is_hvm_domain(d) )
-    {
-        /*
-         * Cross-page emulated writes are only supported for HVM guests;
-         * PV guests ought to know better.
-         */
-        put_page(mfn_to_page(sh_ctxt->mfn[0]));
-        return MAPPING_UNHANDLEABLE;
-    }
     else
     {
         /* This write crosses a page boundary. Translate the second page. */
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 853682190f..593532defc 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -3444,7 +3444,7 @@ int sh_rm_write_access_from_sl1p(struct domain *d, mfn_t 
gmfn,
     ASSERT(mfn_valid(smfn));
 
     /* Remember if we've been told that this process is being torn down */
-    if ( curr->domain == d && is_hvm_domain(d) )
+    if ( curr->domain == d )
         curr->arch.paging.shadow.pagetable_dying
             = mfn_to_page(gmfn)->pagetable_dying;
 
diff --git a/xen/arch/x86/mm/shadow/oos.c b/xen/arch/x86/mm/shadow/oos.c
index 89e8a3b722..956b5ebcba 100644
--- a/xen/arch/x86/mm/shadow/oos.c
+++ b/xen/arch/x86/mm/shadow/oos.c
@@ -577,7 +577,6 @@ int sh_unsync(struct vcpu *v, mfn_t gmfn)
     if ( (pg->shadow_flags &
           ((SHF_page_type_mask & ~SHF_L1_ANY) | SHF_out_of_sync)) ||
          sh_page_has_multiple_shadows(pg) ||
-         !is_hvm_vcpu(v) ||
          !v->domain->arch.paging.shadow.oos_active )
         return 0;
 
--
generated by git-patchbot for /home/xen/git/xen.git#master