[Xen-devel] [PATCH 4/6] xen/x86/pvh: Set up descriptors for 32-bit PVH guests

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
 arch/x86/xen/enlighten.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0b95c9b..7953e68 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1362,12 +1362,12 @@ static void __init xen_boot_params_init_edd(void)
 static void __ref xen_setup_gdt(int cpu)
 {
        if (xen_feature(XENFEAT_auto_translated_physmap)) {
-#ifdef CONFIG_X86_64
                unsigned long dummy;
 
-               load_percpu_segment(cpu); /* We need to access per-cpu area */
+               setup_stack_canary_segment(cpu);
                switch_to_new_gdt(cpu); /* GDT and GS set */
 
+#ifdef CONFIG_X86_64
                /* We are switching of the Xen provided GDT to our HVM mode
                 * GDT. The new GDT has  __KERNEL_CS with CS.L = 1
                 * and we are jumping to reload it.
@@ -1392,8 +1392,16 @@ static void __ref xen_setup_gdt(int cpu)
                loadsegment(ds, 0);
                loadsegment(fs, 0);
 #else
-               /* PVH: TODO Implement. */
-               BUG();
+               asm volatile ("ljmp %1,$1f\n"
+                             "1:\n"
+                             "movl %2,%0\n"
+                             "movl %0,%%ss\n"
+                             "movl %3,%0\n"
+                             "movl %0,%%ds\n"
+                             "movl %0,%%es\n"
+                             : "=&r" (dummy)
+                             : "i" (__KERNEL_CS), "i" (__KERNEL_DS),
+                               "i" (__USER_DS));
 #endif
                return; /* PVH does not need any PV GDT ops. */
        }
-- 
1.8.1.4


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