[Xen-devel] [PATCH] x86/hvm: Fix the use of "hap=0" following c/s c0902a9a143a

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

c/s c0902a9a143a refactored hvm_enable() a little, but dropped the logic which
cleared hap_supported in the case that the user had asked for it off.

This results in Xen booting up, claiming:

  (XEN) HVM: Hardware Assisted Paging (HAP) detected but disabled

but with HAP advertised via sysctl, and XEN_DOMCTL_CDF_hap being accepted in
domain_create().

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Paul Durrant <paul@xxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>

This is a regression from 4.12, so should be fixed before 4.13 ships.
---
 xen/arch/x86/hvm/hvm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index c22cb39cf3..9acd359c99 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -142,7 +142,7 @@ static struct notifier_block cpu_nfb = {
     .notifier_call = cpu_callback
 };
 
-static bool __init hap_supported(const struct hvm_function_table *fns)
+static bool __init hap_supported(struct hvm_function_table *fns)
 {
     if ( !fns->hap_supported )
     {
@@ -152,6 +152,7 @@ static bool __init hap_supported(const struct 
hvm_function_table *fns)
 
     if ( !opt_hap_enabled )
     {
+        fns->hap_supported = 0;
         printk("HVM: Hardware Assisted Paging (HAP) detected but disabled\n");
         return false;
     }
@@ -175,7 +176,7 @@ static int __init hvm_enable(void)
     hvm_enabled = 1;
 
     printk("HVM: %s enabled\n", fns->name);
-    if ( !hap_supported(fns) )
+    if ( !hap_supported(&hvm_funcs) )
         clear_iommu_hap_pt_share();
     else
     {
-- 
2.11.0


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