From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH 1 of 3] apic: record local apic state on boot Date: Wed, 18 May 2011 14:49:50 -0400 Message-ID: <20110518184950.GC14013@dumpdata.com> References: <62a8ce6595ad940a76db.1305742094@andrewcoop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <62a8ce6595ad940a76db.1305742094@andrewcoop> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andrew Cooper Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Wed, May 18, 2011 at 07:08:14PM +0100, Andrew Cooper wrote: > Xen does not store the boot local apic state which leads to problems > when shutting down for a kexec jump. This patch records the boot > state so we can return to the boot state when kexec'ing. > > This is per CPU because all 3 bioses on the boxes I have tested dont > enabled all local apics on boot. As a result, we have to return to > the bios state so the ACPI tables match up with the hardware state > for the booting kernel. Which ACPI table requires this? > > Signed-off-by: Andrew Cooper > > diff -r f531ed84b066 -r 62a8ce6595ad xen/arch/x86/apic.c > --- a/xen/arch/x86/apic.c Tue May 17 17:32:19 2011 +0100 > +++ b/xen/arch/x86/apic.c Wed May 18 19:00:13 2011 +0100 > @@ -74,6 +74,8 @@ u8 __read_mostly apic_verbosity; > static bool_t __initdata opt_x2apic = 1; > boolean_param("x2apic", opt_x2apic); > > +DEFINE_PER_CPU_READ_MOSTLY(enum apic_mode, apic_boot_mode) = APIC_MODE_INVALID; > + > bool_t __read_mostly x2apic_enabled = 0; > bool_t __read_mostly directed_eoi_enabled = 0; > > @@ -1437,6 +1439,41 @@ int __init APIC_init_uniprocessor (void) > return 0; > } > > +/* Needs to be called once per CPU during startup. It records the state the BIOS > + * leaves the local APIC so we can tare back down upon shutdown/crash tare? > + */ > +void __init record_boot_APIC_mode(void) > +{ > + enum apic_mode this_apic_mode; > + u64 msr_contents; > + > + this_apic_mode = APIC_MODE_INVALID; > + > + /* Sanity check - we should only ever run once */ > + BUG_ON( APIC_MODE_INVALID != this_cpu(apic_boot_mode) ); > + > + rdmsrl(MSR_IA32_APICBASE, msr_contents); > + > + /* Reading EXTD bit from the MSR is only valid if CPUID says so, else reserved */ > + if ( cpu_has(¤t_cpu_data, X86_FEATURE_X2APIC) > + && (msr_contents & MSR_IA32_APICBASE_EXTD) ) > + this_apic_mode = APIC_MODE_X2APIC; > + else > + { > + /* EN bit should always be valid as long as we can read the MSR > + * Can anyone confirm this? Email Vivek Goyal. He is the kexec/kdump maintainer. > + */ > + if ( msr_contents & MSR_IA32_APICBASE_ENABLE ) > + this_apic_mode = APIC_MODE_XAPIC; > + else > + this_apic_mode = APIC_MODE_DISABLED; > + } > + > + this_cpu(apic_boot_mode) = this_apic_mode; > + apic_printk(APIC_DEBUG, "APIC boot state is %d on core #%d\n", > + this_apic_mode, smp_processor_id()); This begs of a function to convert those enums to strings.. > +} > + > void check_for_unexpected_msi(unsigned int vector) > { > unsigned long v = apic_read(APIC_ISR + ((vector & ~0x1f) >> 1)); > diff -r f531ed84b066 -r 62a8ce6595ad xen/arch/x86/genapic/probe.c > --- a/xen/arch/x86/genapic/probe.c Tue May 17 17:32:19 2011 +0100 > +++ b/xen/arch/x86/genapic/probe.c Wed May 18 19:00:13 2011 +0100 > @@ -60,6 +60,8 @@ void __init generic_apic_probe(void) > { > int i, changed; > > + record_boot_APIC_mode(); > + The spacing looks odd. > check_x2apic_preenabled(); > cmdline_apic = changed = (genapic != NULL); > > diff -r f531ed84b066 -r 62a8ce6595ad xen/arch/x86/smpboot.c > --- a/xen/arch/x86/smpboot.c Tue May 17 17:32:19 2011 +0100 > +++ b/xen/arch/x86/smpboot.c Wed May 18 19:00:13 2011 +0100 > @@ -388,6 +388,9 @@ void start_secondary(void *unused) > > microcode_resume_cpu(cpu); > > + /* Record boot apic state */ > + record_boot_APIC_mode(); > + > wmb(); > startup_cpu_idle_loop(); > } > diff -r f531ed84b066 -r 62a8ce6595ad xen/include/asm-x86/apic.h > --- a/xen/include/asm-x86/apic.h Tue May 17 17:32:19 2011 +0100 > +++ b/xen/include/asm-x86/apic.h Wed May 18 19:00:13 2011 +0100 > @@ -21,6 +21,16 @@ > #define IO_APIC_REDIR_DEST_LOGICAL 0x00800 > #define IO_APIC_REDIR_DEST_PHYSICAL 0x00000 > > +/* Possible APIC states */ > +enum apic_mode { APIC_MODE_INVALID, /* Not set yet */ > + APIC_MODE_DISABLED, /* Some bioses disable by default for compatability */ > + APIC_MODE_XAPIC, /* xAPIC mode - default upon chipset reset */ > + APIC_MODE_X2APIC /* x2APIC mode - common for large smp machines */ > +}; > + > +/* PerCPU local APIC boot mode - so we can taredown to bios state */ taredown? > +DECLARE_PER_CPU(enum apic_mode, apic_boot_mode); > + > extern u8 apic_verbosity; > extern bool_t x2apic_enabled; > extern bool_t directed_eoi_enabled; > @@ -203,6 +213,7 @@ extern void disable_APIC_timer(void); > extern void enable_APIC_timer(void); > extern int lapic_suspend(void); > extern int lapic_resume(void); > +extern void record_boot_APIC_mode(void); > > extern int check_nmi_watchdog (void); > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel