Neither p2m_mmio_dm nor the types p2m_is_readonly() checks for are
applicable to PV; specifically get_gfn() won't ever return such a type
for PV domains. Adjacent to those checks is yet another is_hvm_...()
one. With that block made conditional, another conditional block near
the end of the function can be widened.
Furthermore the shadow_mode_refcounts() check immediately ahead of the
aforementioned newly inserted #ifdef renders redundant two subsequent
is_hvm_domain() checks (the latter of which was already redundant with
the former).
Also guest_mode() checks are pointless when we already know we're
dealing with a HVM domain.
Finally style-adjust a comment which otherwise would be fully visible as
patch context anyway.
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
I'm not convinced of the usefulness of the ASSERT() immediately after
the "mmio" label. Additionally I think the code there would better move
to the single place where we presently have "goto mmio", bringing things
more in line with the other handle_mmio_with_translation() invocation
site.
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -2158,8 +2158,8 @@ 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;
@@ -2583,6 +2583,7 @@ 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 )
{
@@ -2614,13 +2615,14 @@ static int cf_check sh_page_fault(
perfc_incr(shadow_fault_emulate_wp);
goto emulate;
}
+#endif
perfc_incr(shadow_fault_fixed);
d->arch.paging.log_dirty.fault_count++;
sh_reset_early_unshadow(v);
trace_shadow_fixup(gw.l1e, va);
- done:
+ done: __maybe_unused;
sh_audit_gw(v, &gw);
SHADOW_PRINTK("fixed\n");
shadow_audit_tables(v);
@@ -2629,9 +2631,10 @@ static int cf_check sh_page_fault(
return EXCRET_fault_fixed;
emulate:
- if ( !shadow_mode_refcounts(d) || !guest_mode(regs) )
+ if ( !shadow_mode_refcounts(d) )
goto not_a_shadow_fault;
+#ifdef CONFIG_HVM
/*
* We do not emulate user writes. Instead we use them as a hint that the
* page is no longer a page table. This behaviour differs from native, but
@@ -2653,17 +2656,11 @@ static int cf_check sh_page_fault(
* caught by user-mode page-table check above.
*/
emulate_readonly:
- if ( !is_hvm_domain(d) )
- {
- ASSERT_UNREACHABLE();
- goto not_a_shadow_fault;
- }
-
-#ifdef CONFIG_HVM
- /* Unshadow if we are writing to a toplevel pagetable that is
- * flagged as a dying process, and that is not currently used. */
- if ( sh_mfn_is_a_page_table(gmfn) && is_hvm_domain(d) &&
- mfn_to_page(gmfn)->pagetable_dying )
+ /*
+ * Unshadow if we are writing to a toplevel pagetable that is
+ * flagged as a dying process, and that is not currently used.
+ */
+ if ( sh_mfn_is_a_page_table(gmfn) && mfn_to_page(gmfn)->pagetable_dying )
{
int used = 0;
struct vcpu *tmp;
@@ -2867,13 +2864,9 @@ static int cf_check sh_page_fault(
emulate_done:
SHADOW_PRINTK("emulated\n");
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));
+ ASSERT(is_hvm_domain(d));
perfc_incr(shadow_fault_mmio);
sh_audit_gw(v, &gw);
SHADOW_PRINTK("mmio %#"PRIpaddr"\n", gpa);
@@ -2884,9 +2877,7 @@ static int cf_check sh_page_fault(
trace_shadow_gen(TRC_SHADOW_MMIO, va);
return (handle_mmio_with_translation(va, gpa >> PAGE_SHIFT, access)
? EXCRET_fault_fixed : 0);
-#else
- BUG();
-#endif
+#endif /* CONFIG_HVM */
not_a_shadow_fault:
sh_audit_gw(v, &gw);
