From aa96a3c686b001a651c86dcb5b0b73d1a9b1d1ca Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 5 Sep 2013 17:45:54 +0930 Subject: [PATCH] lguest: fix GPF in guest when using gdb. Since the Guest is in ring 1, it can't read the debug registers: doing so gives a number of nasty messages: (gdb) run Starting program: /bin/sleep [ 31.170230] general protection fault: 0000 [#1] SMP [ 31.170230] Modules linked in: [ 31.170230] CPU: 0 PID: 2678 Comm: sleep Not tainted 3.11.0+ #64 [ 31.170230] task: cc5c09b0 ti: cc79c000 task.ti: cc79c000 [ 31.170230] EIP: 0061:[] EFLAGS: 00000097 CPU: 0 [ 31.170230] EIP is at native_get_debugreg+0x58/0x70 [ 31.170230] EAX: 00000006 EBX: cc79dfb4 ECX: b7fff918 EDX: 00000000 [ 31.170230] ESI: cc5c09b0 EDI: 00000000 EBP: cc79df84 ESP: cc79df84 [ 31.170230] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0069 [ 31.170230] CR0: 00000008 CR2: 081ba69a CR3: 0e2f2000 CR4: 00000000 Signed-off-by: Rusty Russell --- arch/x86/lguest/boot.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 7c1fde50ecb0..bdf8532494fe 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1056,6 +1056,12 @@ static void lguest_load_sp0(struct tss_struct *tss, } /* Let's just say, I wouldn't do debugging under a Guest. */ +static unsigned long lguest_get_debugreg(int regno) +{ + /* FIXME: Implement */ + return 0; +} + static void lguest_set_debugreg(int regno, unsigned long value) { /* FIXME: Implement */ @@ -1303,6 +1309,7 @@ __init void lguest_init(void) pv_cpu_ops.load_tr_desc = lguest_load_tr_desc; pv_cpu_ops.set_ldt = lguest_set_ldt; pv_cpu_ops.load_tls = lguest_load_tls; + pv_cpu_ops.get_debugreg = lguest_get_debugreg; pv_cpu_ops.set_debugreg = lguest_set_debugreg; pv_cpu_ops.clts = lguest_clts; pv_cpu_ops.read_cr0 = lguest_read_cr0; -- 2.20.1