[Xen-devel] [PATCH 3/4] introduce boot parameter for setting XENFEAT_virtual_p2m

[Juergen Gross <jgross@xxxxxxxx>]

Introduce a new boot parameter "virt_p2m" to be able to set
XENFEAT_virtual_p2m for a pv domain.

As long as Xen tools and kdump don't support this new feature it is
turned off by default.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/arch/x86/domain.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index d98aabd..ccb54f6 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -2166,8 +2166,44 @@ static int __init init_vcpu_kick_softirq(void)
 }
 __initcall(init_vcpu_kick_softirq);
 
+#define VIRT_P2M_DOM0        0x01
+#define VIRT_P2M_DOM0_LARGE  0x02
+#define VIRT_P2M_DOMU        0x04
+#define VIRT_P2M_DOMU_LARGE  0x08
+static unsigned virt_p2m = 0;
+
+static void __init parse_virt_p2m(const char *s)
+{
+    char *ss;
+    int b;
+
+    do {
+        ss = strchr(s, ',');
+        if ( ss )
+            *ss = '\0';
+
+        b = parse_bool(s);
+        if ( b == 0 )
+            virt_p2m = 0;
+        else if ( b == 1 )
+            virt_p2m = VIRT_P2M_DOM0 | VIRT_P2M_DOMU;
+        else if ( !strcmp(s, "dom0") )
+            virt_p2m |= VIRT_P2M_DOM0;
+        else if ( !strcmp(s, "dom0_large") )
+            virt_p2m |= VIRT_P2M_DOM0_LARGE;
+        else if ( !strcmp(s, "domu") )
+            virt_p2m |= VIRT_P2M_DOMU;
+        else if ( !strcmp(s, "domu_large") )
+            virt_p2m |= VIRT_P2M_DOMU_LARGE;
+
+        s = ss + 1;
+    } while ( ss );
+}
+custom_param("virt_p2m", parse_virt_p2m);
+
 uint32_t arch_get_features(struct domain *d, unsigned int submap_idx)
 {
+#define DOM_IS_LARGE(d) ((d)->max_pages > 1U << 27)
     uint32_t submap = 0;
 
     switch ( submap_idx )
@@ -2179,6 +2215,20 @@ uint32_t arch_get_features(struct domain *d, unsigned 
int submap_idx)
             submap |= (1U << XENFEAT_mmu_pt_update_preserve_ad) |
                       (1U << XENFEAT_highmem_assist) |
                       (1U << XENFEAT_gnttab_map_avail_bits);
+            if ( is_hardware_domain(d) )
+            {
+                if ( virt_p2m & VIRT_P2M_DOM0 )
+                    submap |= 1U << XENFEAT_virtual_p2m;
+                if ( DOM_IS_LARGE(d) && virt_p2m & VIRT_P2M_DOM0_LARGE )
+                    submap |= 1U << XENFEAT_virtual_p2m;
+            }
+            else
+            {
+                if ( virt_p2m & VIRT_P2M_DOMU )
+                    submap |= 1U << XENFEAT_virtual_p2m;
+                if ( DOM_IS_LARGE(d) && virt_p2m & VIRT_P2M_DOMU_LARGE )
+                    submap |= 1U << XENFEAT_virtual_p2m;
+            }
             break;
         case guest_type_pvh:
             submap |= (1U << XENFEAT_hvm_safe_pvclock) |
-- 
2.1.2


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