From: Stanislav Kinsburskii <skinsburskii@xxxxxxxxxxxxxxxxxxx> Sent: Wednesday, November 2, 2022 3:07 PM > > And rework the code to use it instead of the physical address, which isn't > required by itself. > > This is a cleanup and precursor patch for upcoming support for TSC page > mapping into Microsoft Hypervisor root partition, where TSC PFN will be > defined by the hypervisor and not by the kernel. > > Signed-off-by: Stanislav Kinsburskiy <stanislav.kinsburskiy@xxxxxxxxx> > CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> > CC: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > CC: Wei Liu <wei.liu@xxxxxxxxxx> > CC: Dexuan Cui <decui@xxxxxxxxxxxxx> > CC: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > CC: linux-hyperv@xxxxxxxxxxxxxxx > CC: linux-kernel@xxxxxxxxxxxxxxx > --- > drivers/clocksource/hyperv_timer.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c > index c4dbf40a3d3e..d447bc99a399 100644 > --- a/drivers/clocksource/hyperv_timer.c > +++ b/drivers/clocksource/hyperv_timer.c > @@ -367,6 +367,12 @@ static union { > } tsc_pg __aligned(PAGE_SIZE); > > static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page; > +static unsigned long tsc_pfn; > + > +static unsigned long hv_get_tsc_pfn(void) > +{ > + return tsc_pfn; > +} > > struct ms_hyperv_tsc_page *hv_get_tsc_page(void) > { > @@ -408,13 +414,12 @@ static void suspend_hv_clock_tsc(struct clocksource *arg) > > static void resume_hv_clock_tsc(struct clocksource *arg) > { > - phys_addr_t phys_addr = virt_to_phys(tsc_page); > union hv_reference_tsc_msr tsc_msr; > > /* Re-enable the TSC page */ > tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); > tsc_msr.enable = 1; > - tsc_msr.pfn = __phys_to_pfn(phys_addr); > + tsc_msr.pfn = tsc_pfn; > hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); > } > > @@ -498,7 +503,6 @@ static __always_inline void hv_setup_sched_clock(void > *sched_clock) {} > static bool __init hv_init_tsc_clocksource(void) > { > union hv_reference_tsc_msr tsc_msr; > - phys_addr_t phys_addr; > > if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) > return false; > @@ -523,7 +527,7 @@ static bool __init hv_init_tsc_clocksource(void) > } > > hv_read_reference_counter = read_hv_clock_tsc; > - phys_addr = virt_to_phys(hv_get_tsc_page()); > + tsc_pfn = __phys_to_pfn(virt_to_phys(tsc_page)); I probably wasn't specific enough when I said "your choice" in my previous comments. This sets tsc_pfn to a guest PFN. In a guest with page size other than 4096, it will be wrong when stored into tsc_msr.pfn a few lines below. hyperv_timer.c is currently architecture and page size independent, and it needs to stay that way. > /* > * The Hyper-V TLFS specifies to preserve the value of reserved > @@ -534,7 +538,7 @@ static bool __init hv_init_tsc_clocksource(void) > */ > tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); > tsc_msr.enable = 1; > - tsc_msr.pfn = __phys_to_pfn(phys_addr); > + tsc_msr.pfn = tsc_pfn; > hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); > > clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); >