From d89149543d5c791af2dc43f59edc2c23b45128f6 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 1 Jul 2011 20:41:43 +0100 Subject: [PATCH] x86/EFI: fix interrupt and fault handling during runtime services calls The missing piece was the setting up of an accessible GDT prior to switching page tables (and reverting to the original setting after having established the normal page tables again afterwards). Signed-off-by: Jan Beulich --- xen/arch/x86/efi/runtime.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/xen/arch/x86/efi/runtime.c b/xen/arch/x86/efi/runtime.c index 8274e22f3e..6286b6a1c8 100644 --- a/xen/arch/x86/efi/runtime.c +++ b/xen/arch/x86/efi/runtime.c @@ -44,6 +44,17 @@ unsigned long efi_rs_enter(void) /* prevent fixup_page_fault() from doing anything */ irq_enter(); + if ( !is_hvm_vcpu(current) && !is_idle_vcpu(current) ) + { + struct desc_ptr gdt_desc = { + .limit = LAST_RESERVED_GDT_BYTE, + .base = (unsigned long)(per_cpu(gdt_table, smp_processor_id()) - + FIRST_RESERVED_GDT_ENTRY) + }; + + asm volatile ( "lgdt %0" : : "m" (gdt_desc) ); + } + write_cr3(virt_to_maddr(efi_l4_pgtable)); return cr3; @@ -52,6 +63,15 @@ unsigned long efi_rs_enter(void) void efi_rs_leave(unsigned long cr3) { write_cr3(cr3); + if ( !is_hvm_vcpu(current) && !is_idle_vcpu(current) ) + { + struct desc_ptr gdt_desc = { + .limit = LAST_RESERVED_GDT_BYTE, + .base = GDT_VIRT_START(current) + }; + + asm volatile ( "lgdt %0" : : "m" (gdt_desc) ); + } irq_exit(); spin_unlock(&efi_rs_lock); } -- 2.30.2