[xen master] x86/shadow: move dm-mmio handling code in sh_page_fault()

[patchbot@xxxxxxx]

commit 4e8205f4fdb9a043170439c9c63542ddff816849
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Feb 27 13:34:30 2023 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Feb 27 13:34:30 2023 +0100

    x86/shadow: move dm-mmio handling code in sh_page_fault()
    
    Do away with the partly mis-named "mmio" label there, which really is
    only about emulated MMIO. Move the code to the place where the sole
    "goto" was. Re-order steps slightly: Assertion first, perfc increment
    outside of the locked region, and "gpa" calculation closer to the first
    use of the variable. Also make the HVM conditional cover the entire
    if(), as p2m_mmio_dm isn't applicable to PV; specifically get_gfn()
    won't ever return this type for PV domains.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/mm/shadow/multi.c | 43 +++++++++++++++++++++---------------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 5f3e175bbe..be67e9cb62 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -2161,8 +2161,8 @@ static int cf_check sh_page_fault(
     gfn_t gfn = _gfn(0);
     mfn_t gmfn, sl1mfn = _mfn(0);
     shadow_l1e_t sl1e, *ptr_sl1e;
-    paddr_t gpa;
 #ifdef CONFIG_HVM
+    paddr_t gpa;
     struct sh_emulate_ctxt emul_ctxt;
     const struct x86_emulate_ops *emul_ops;
     int r;
@@ -2586,13 +2586,33 @@ static int cf_check sh_page_fault(
         goto emulate;
     }
 
+#ifdef CONFIG_HVM
+
     /* Need to hand off device-model MMIO to the device model */
     if ( p2mt == p2m_mmio_dm )
     {
+        ASSERT(is_hvm_vcpu(v));
+        if ( !guest_mode(regs) )
+            goto not_a_shadow_fault;
+
+        sh_audit_gw(v, &gw);
         gpa = guest_walk_to_gpa(&gw);
-        goto mmio;
+        SHADOW_PRINTK("mmio %#"PRIpaddr"\n", gpa);
+        shadow_audit_tables(v);
+        sh_reset_early_unshadow(v);
+
+        paging_unlock(d);
+        put_gfn(d, gfn_x(gfn));
+
+        perfc_incr(shadow_fault_mmio);
+        trace_shadow_gen(TRC_SHADOW_MMIO, va);
+
+        return handle_mmio_with_translation(va, gpa >> PAGE_SHIFT, access)
+               ? EXCRET_fault_fixed : 0;
     }
 
+#endif /* CONFIG_HVM */
+
     /* Ignore attempts to write to read-only memory. */
     if ( p2m_is_readonly(p2mt) && (ft == ft_demand_write) )
         goto emulate_readonly; /* skip over the instruction */
@@ -2865,25 +2885,6 @@ static int cf_check sh_page_fault(
     return EXCRET_fault_fixed;
 #endif /* CONFIG_HVM */
 
- mmio:
-    if ( !guest_mode(regs) )
-        goto not_a_shadow_fault;
-#ifdef CONFIG_HVM
-    ASSERT(is_hvm_vcpu(v));
-    perfc_incr(shadow_fault_mmio);
-    sh_audit_gw(v, &gw);
-    SHADOW_PRINTK("mmio %#"PRIpaddr"\n", gpa);
-    shadow_audit_tables(v);
-    sh_reset_early_unshadow(v);
-    paging_unlock(d);
-    put_gfn(d, gfn_x(gfn));
-    trace_shadow_gen(TRC_SHADOW_MMIO, va);
-    return (handle_mmio_with_translation(va, gpa >> PAGE_SHIFT, access)
-            ? EXCRET_fault_fixed : 0);
-#else
-    BUG();
-#endif
-
  not_a_shadow_fault:
     sh_audit_gw(v, &gw);
     SHADOW_PRINTK("not a shadow fault\n");
--
generated by git-patchbot for /home/xen/git/xen.git#master