Michael, On Mon, 22 Oct 2018, Michael Kelley wrote:
> pit_shutdown() doesn't work on Hyper-V because of a quirk in the > PIT emulation. After shutdown the emulated PIT continues to interrupt > @18.2 HZ. This problem exists in all versions of Hyper-V and just > had not previously been noticed. So replace the normal PIT shutdown > function with an alternate version that works on Hyper-V. > > The alternate shutdown function could go in the i8253.c module, > but it seems better to keep the hack with the Hyper-V code rather > than clutter up i8253.c with #ifdef CONFIG_HYPERV. You can avoid the ideffery completely. Something like the uncompiled patch (lacks comments) below keeps everything in i8253 and should just work. Thanks, tglx 8<------------------- diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c index 9c38895542f4..9b5d2259c2e5 100644 --- a/drivers/clocksource/i8253.c +++ b/drivers/clocksource/i8253.c @@ -10,6 +10,7 @@ #include <linux/module.h> #include <linux/i8253.h> #include <linux/smp.h> +#include <linux/hypervisor.h> /* * Protects access to I/O ports @@ -109,9 +110,10 @@ static int pit_shutdown(struct clock_event_device *evt) raw_spin_lock(&i8253_lock); outb_p(0x30, PIT_MODE); - outb_p(0, PIT_CH0); - outb_p(0, PIT_CH0); - + if (!hypervisor_is_mshyperv()) { + outb_p(0, PIT_CH0); + outb_p(0, PIT_CH0); + } raw_spin_unlock(&i8253_lock); return 0; } diff --git a/include/linux/hypervisor.h b/include/linux/hypervisor.h index fc08b433c856..2ab7303675f3 100644 --- a/include/linux/hypervisor.h +++ b/include/linux/hypervisor.h @@ -10,6 +10,7 @@ #ifdef CONFIG_X86 #include <asm/jailhouse_para.h> +#include <asm/hypervisor.h> #include <asm/x86_init.h> static inline void hypervisor_pin_vcpu(int cpu) @@ -17,6 +18,11 @@ static inline void hypervisor_pin_vcpu(int cpu) x86_platform.hyper.pin_vcpu(cpu); } +static inline bool hypervisor_is_mshyperv(void) +{ + return hypervisor_is_type(X86_HYPER_MS_HYPERV); +} + #else /* !CONFIG_X86 */ #include <linux/of.h> @@ -30,6 +36,11 @@ static inline bool jailhouse_paravirt(void) return of_find_compatible_node(NULL, NULL, "jailhouse,cell"); } +static inline bool hypervisor_is_mshyperv(void) +{ + return false; +} + #endif /* !CONFIG_X86 */ #endif /* __LINUX_HYPEVISOR_H */