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authorJuergen Gross <jgross@suse.com>2017-11-02 10:19:21 +0100
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2017-11-06 15:50:17 -0500
commit8dca4d96c7d8058e7c97daad9ae0a76569ea31e6 (patch)
tree171e808f1a9c34a655325193addb4206e8f5d1ff /drivers/xen/grant-table.c
parent223c8f3349f9ce52847dfa266b32761ac223b9ac (diff)
xen: select grant interface version
Grant v2 will be needed in cases where a frame number in the grant table can exceed 32 bits. For PV guests this is a host feature, while for HVM guests this is a guest feature. So select grant v2 in case frame numbers can be larger than 32 bits and grant v1 else. For testing purposes add a way to specify the grant interface version via a boot parameter. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen/grant-table.c')
-rw-r--r--drivers/xen/grant-table.c35
1 files changed, 33 insertions, 2 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 573e7fe9b147..fa152832e0e6 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -33,6 +33,7 @@
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+#include <linux/bootmem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/slab.h>
@@ -43,6 +44,7 @@
#include <linux/hardirq.h>
#include <linux/workqueue.h>
#include <linux/ratelimit.h>
+#include <linux/moduleparam.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
@@ -52,6 +54,9 @@
#include <xen/hvc-console.h>
#include <xen/swiotlb-xen.h>
#include <xen/balloon.h>
+#ifdef CONFIG_X86
+#include <asm/xen/cpuid.h>
+#endif
#include <asm/xen/hypercall.h>
#include <asm/xen/interface.h>
@@ -68,6 +73,8 @@ static int gnttab_free_count;
static grant_ref_t gnttab_free_head;
static DEFINE_SPINLOCK(gnttab_list_lock);
struct grant_frames xen_auto_xlat_grant_frames;
+static unsigned int xen_gnttab_version;
+module_param_named(version, xen_gnttab_version, uint, 0);
static union {
struct grant_entry_v1 *v1;
@@ -1177,12 +1184,36 @@ static const struct gnttab_ops gnttab_v2_ops = {
.query_foreign_access = gnttab_query_foreign_access_v2,
};
+static bool gnttab_need_v2(void)
+{
+#ifdef CONFIG_X86
+ uint32_t base, width;
+
+ if (xen_pv_domain()) {
+ base = xen_cpuid_base();
+ if (cpuid_eax(base) < 5)
+ return false; /* Information not available, use V1. */
+ width = cpuid_ebx(base + 5) &
+ XEN_CPUID_MACHINE_ADDRESS_WIDTH_MASK;
+ return width > 32 + PAGE_SHIFT;
+ }
+#endif
+ return !!(max_possible_pfn >> 32);
+}
+
static void gnttab_request_version(void)
{
- int rc;
+ long rc;
struct gnttab_set_version gsv;
- gsv.version = 1;
+ if (gnttab_need_v2())
+ gsv.version = 2;
+ else
+ gsv.version = 1;
+
+ /* Boot parameter overrides automatic selection. */
+ if (xen_gnttab_version >= 1 && xen_gnttab_version <= 2)
+ gsv.version = xen_gnttab_version;
rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
if (rc == 0 && gsv.version == 2)