From 3154d1d8a3f7d057044667d744f02202a40826cd Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Wed, 10 Oct 2012 13:25:48 -0400 Subject: [PATCH] xen/bootup: allow {read|write}_cr8 pvops call. commit 1a7bbda5b1ab0e02622761305a32dc38735b90b2 upstream. We actually do not do anything about it. Just return a default value of zero and if the kernel tries to write anything but 0 we BUG_ON. This fixes the case when an user tries to suspend the machine and it blows up in save_processor_state b/c 'read_cr8' is set to NULL and we get: kernel BUG at /home/konrad/ssd/linux/arch/x86/include/asm/paravirt.h:100! invalid opcode: 0000 [#1] SMP Pid: 2687, comm: init.late Tainted: G O 3.6.0upstream-00002-gac264ac-dirty #4 Bochs Bochs RIP: e030:[] [] save_processor_state+0x212/0x270 .. snip.. Call Trace: [] do_suspend_lowlevel+0xf/0xac [] ? x86_acpi_suspend_lowlevel+0x10c/0x150 [] acpi_suspend_enter+0x57/0xd5 Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Ben Hutchings --- arch/x86/xen/enlighten.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 16378b457b27..69b9ef6ce55a 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -818,7 +818,16 @@ static void xen_write_cr4(unsigned long cr4) native_write_cr4(cr4); } - +#ifdef CONFIG_X86_64 +static inline unsigned long xen_read_cr8(void) +{ + return 0; +} +static inline void xen_write_cr8(unsigned long val) +{ + BUG_ON(val); +} +#endif static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) { int ret; @@ -987,6 +996,11 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { .read_cr4_safe = native_read_cr4_safe, .write_cr4 = xen_write_cr4, +#ifdef CONFIG_X86_64 + .read_cr8 = xen_read_cr8, + .write_cr8 = xen_write_cr8, +#endif + .wbinvd = native_wbinvd, .read_msr = native_read_msr_safe, -- 2.39.5