diff options
Diffstat (limited to 'drivers/clocksource/hyperv_timer.c')
| -rw-r--r-- | drivers/clocksource/hyperv_timer.c | 86 |
1 files changed, 60 insertions, 26 deletions
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index bb47610bbd1c..c0cef92b12b8 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -21,6 +21,7 @@ #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/acpi.h> +#include <linux/hyperv.h> #include <clocksource/hyperv_timer.h> #include <asm/hyperv-tlfs.h> #include <asm/mshyperv.h> @@ -366,9 +367,18 @@ static union { u8 reserved[PAGE_SIZE]; } tsc_pg __aligned(PAGE_SIZE); +static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page; +static unsigned long tsc_pfn; + +unsigned long hv_get_tsc_pfn(void) +{ + return tsc_pfn; +} +EXPORT_SYMBOL_GPL(hv_get_tsc_pfn); + struct ms_hyperv_tsc_page *hv_get_tsc_page(void) { - return &tsc_pg.page; + return tsc_page; } EXPORT_SYMBOL_GPL(hv_get_tsc_page); @@ -395,25 +405,24 @@ static u64 notrace read_hv_sched_clock_tsc(void) static void suspend_hv_clock_tsc(struct clocksource *arg) { - u64 tsc_msr; + union hv_reference_tsc_msr tsc_msr; /* Disable the TSC page */ - tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC); - tsc_msr &= ~BIT_ULL(0); - hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); + tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); + tsc_msr.enable = 0; + hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); } static void resume_hv_clock_tsc(struct clocksource *arg) { - phys_addr_t phys_addr = virt_to_phys(&tsc_pg); - u64 tsc_msr; + union hv_reference_tsc_msr tsc_msr; /* Re-enable the TSC page */ - tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC); - tsc_msr &= GENMASK_ULL(11, 0); - tsc_msr |= BIT_ULL(0) | (u64)phys_addr; - hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); + tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); + tsc_msr.enable = 1; + tsc_msr.pfn = tsc_pfn; + hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); } #ifdef HAVE_VDSO_CLOCKMODE_HVCLOCK @@ -495,15 +504,11 @@ static __always_inline void hv_setup_sched_clock(void *sched_clock) {} static bool __init hv_init_tsc_clocksource(void) { - u64 tsc_msr; - phys_addr_t phys_addr; + union hv_reference_tsc_msr tsc_msr; if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) return false; - if (hv_root_partition) - return false; - /* * If Hyper-V offers TSC_INVARIANT, then the virtualized TSC correctly * handles frequency and offset changes due to live migration, @@ -521,19 +526,31 @@ 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()); /* - * The Hyper-V TLFS specifies to preserve the value of reserved - * bits in registers. So read the existing value, preserve the - * low order 12 bits, and add in the guest physical address - * (which already has at least the low 12 bits set to zero since - * it is page aligned). Also set the "enable" bit, which is bit 0. + * TSC page mapping works differently in root compared to guest. + * - In guest partition the guest PFN has to be passed to the + * hypervisor. + * - In root partition it's other way around: it has to map the PFN + * provided by the hypervisor. + * But it can't be mapped right here as it's too early and MMU isn't + * ready yet. So, we only set the enable bit here and will remap the + * page later in hv_remap_tsc_clocksource(). + * + * It worth mentioning, that TSC clocksource read function + * (read_hv_clock_tsc) has a MSR-based fallback mechanism, used when + * TSC page is zeroed (which is the case until the PFN is remapped) and + * thus TSC clocksource will work even without the real TSC page + * mapped. */ - tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC); - tsc_msr &= GENMASK_ULL(11, 0); - tsc_msr = tsc_msr | 0x1 | (u64)phys_addr; - hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); + tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); + if (hv_root_partition) + tsc_pfn = tsc_msr.pfn; + else + tsc_pfn = HVPFN_DOWN(virt_to_phys(tsc_page)); + tsc_msr.enable = 1; + 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); @@ -565,3 +582,20 @@ void __init hv_init_clocksource(void) hv_sched_clock_offset = hv_read_reference_counter(); hv_setup_sched_clock(read_hv_sched_clock_msr); } + +void __init hv_remap_tsc_clocksource(void) +{ + if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) + return; + + if (!hv_root_partition) { + WARN(1, "%s: attempt to remap TSC page in guest partition\n", + __func__); + return; + } + + tsc_page = memremap(tsc_pfn << HV_HYP_PAGE_SHIFT, sizeof(tsc_pg), + MEMREMAP_WB); + if (!tsc_page) + pr_err("Failed to remap Hyper-V TSC page.\n"); +} |