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 <andrew.cooper3@xxxxxxxxxx>
>
> 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);
>
>
> _______________________________________________
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
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