[Xen-devel] [PATCH v5 6/7] xen/guest: prepare hypervisor ops to use alternative calls

From: Roger Pau Monne <roger.pau@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	Paul Durrant <pdurrant@amazon.com>,
	Jan Beulich <jbeulich@suse.com>, Wei Liu <wl@xen.org>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: [Xen-devel] [PATCH v5 6/7] xen/guest: prepare hypervisor ops to use alternative calls
Date: Wed, 19 Feb 2020 18:43:53 +0100	[thread overview]
Message-ID: <20200219174354.84726-7-roger.pau@citrix.com> (raw)
In-Reply-To: <20200219174354.84726-1-roger.pau@citrix.com>

Adapt the hypervisor ops framework so it can be used with the
alternative calls framework. So far no hooks are modified to make use
of the alternatives patching, as they are not in any hot path.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Wei Liu <wl@xen.org>
Reviewed-by: Paul Durrant <pdurrant@amazon.com>
---
Changes since v3:
 - New in this version.
---
 xen/arch/x86/guest/hyperv/hyperv.c |  2 +-
 xen/arch/x86/guest/hypervisor.c    | 41 +++++++++++++++---------------
 xen/arch/x86/guest/xen/xen.c       |  2 +-
 3 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/xen/arch/x86/guest/hyperv/hyperv.c b/xen/arch/x86/guest/hyperv/hyperv.c
index fabc62b0d6..70f4cd5ae0 100644
--- a/xen/arch/x86/guest/hyperv/hyperv.c
+++ b/xen/arch/x86/guest/hyperv/hyperv.c
@@ -199,7 +199,7 @@ static void __init e820_fixup(struct e820map *e820)
         panic("Unable to reserve Hyper-V hypercall range\n");
 }
 
-static const struct hypervisor_ops ops = {
+static const struct hypervisor_ops __initdata ops = {
     .name = "Hyper-V",
     .setup = setup,
     .ap_setup = ap_setup,
diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c
index 5fd433c8d4..647cdb1367 100644
--- a/xen/arch/x86/guest/hypervisor.c
+++ b/xen/arch/x86/guest/hypervisor.c
@@ -24,52 +24,53 @@
 #include <asm/cache.h>
 #include <asm/guest.h>
 
-static const struct hypervisor_ops *__read_mostly ops;
+static struct hypervisor_ops __read_mostly ops;
 
 const char *__init hypervisor_probe(void)
 {
+    const struct hypervisor_ops *fns;
+
     if ( !cpu_has_hypervisor )
         return NULL;
 
-    ops = xg_probe();
-    if ( ops )
-        return ops->name;
+    fns = xg_probe();
+    if ( !fns )
+        /*
+         * Detection of Hyper-V must come after Xen to avoid false positive due
+         * to viridian support
+         */
+        fns = hyperv_probe();
 
-    /*
-     * Detection of Hyper-V must come after Xen to avoid false positive due
-     * to viridian support
-     */
-    ops = hyperv_probe();
-    if ( ops )
-        return ops->name;
+    if ( fns )
+        ops = *fns;
 
-    return NULL;
+    return ops.name;
 }
 
 void __init hypervisor_setup(void)
 {
-    if ( ops && ops->setup )
-        ops->setup();
+    if ( ops.setup )
+        ops.setup();
 }
 
 int hypervisor_ap_setup(void)
 {
-    if ( ops && ops->ap_setup )
-        return ops->ap_setup();
+    if ( ops.ap_setup )
+        return ops.ap_setup();
 
     return 0;
 }
 
 void hypervisor_resume(void)
 {
-    if ( ops && ops->resume )
-        ops->resume();
+    if ( ops.resume )
+        ops.resume();
 }
 
 void __init hypervisor_e820_fixup(struct e820map *e820)
 {
-    if ( ops && ops->e820_fixup )
-        ops->e820_fixup(e820);
+    if ( ops.e820_fixup )
+        ops.e820_fixup(e820);
 }
 
 /*
diff --git a/xen/arch/x86/guest/xen/xen.c b/xen/arch/x86/guest/xen/xen.c
index 3cf8f667a1..f151b07548 100644
--- a/xen/arch/x86/guest/xen/xen.c
+++ b/xen/arch/x86/guest/xen/xen.c
@@ -324,7 +324,7 @@ static void __init e820_fixup(struct e820map *e820)
         pv_shim_fixup_e820(e820);
 }
 
-static const struct hypervisor_ops ops = {
+static const struct hypervisor_ops __initdata ops = {
     .name = "Xen",
     .setup = setup,
     .ap_setup = ap_setup,
-- 
2.25.0


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