Re: [PATCH V2 1/2] clocksource/Hyper-v: Allocate Hyper-V tsc page statically
From: Daniel Lezcano <hidden>
Date: 2019-08-16 15:00:29
Also in:
linux-arch, lkml
On 14/08/2019 14:32, lantianyu1986@gmail.com wrote:
From: Tianyu Lan <redacted> Prepare to add Hyper-V sched clock callback and move Hyper-V Reference TSC initialization much earlier in the boot process. Earlier initialization is needed so that it happens while the timestamp value is still 0 and no discontinuity in the timestamp will occur when pv_ops.time.sched_clock calculates its offset. The earlier initialization requires that the Hyper-V TSC page be allocated statically instead of with vmalloc(), so fixup the references to the TSC page and the method of getting its physical address. Signed-off-by: Tianyu Lan <redacted>
Acked-by: Daniel Lezcano <redacted>
quoted hunk ↗ jump to hunk
--- Change since v1: - Update commit log - Remove and operation of tsc page's va with PAGE_MASK arch/x86/entry/vdso/vma.c | 2 +- drivers/clocksource/hyperv_timer.c | 12 ++++-------- 2 files changed, 5 insertions(+), 9 deletions(-)diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 349a61d8bf34..f5937742b290 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c@@ -122,7 +122,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK)) return vmf_insert_pfn(vma, vmf->address, - vmalloc_to_pfn(tsc_pg)); + virt_to_phys(tsc_pg) >> PAGE_SHIFT); } return VM_FAULT_SIGBUS;diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index ba2c79e6a0ee..432aa331df04 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c@@ -214,17 +214,17 @@ EXPORT_SYMBOL_GPL(hyperv_cs); #ifdef CONFIG_HYPERV_TSCPAGE -static struct ms_hyperv_tsc_page *tsc_pg; +static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE); struct ms_hyperv_tsc_page *hv_get_tsc_page(void) { - return tsc_pg; + return &tsc_pg; } EXPORT_SYMBOL_GPL(hv_get_tsc_page); static u64 notrace read_hv_sched_clock_tsc(void) { - u64 current_tick = hv_read_tsc_page(tsc_pg); + u64 current_tick = hv_read_tsc_page(&tsc_pg); if (current_tick == U64_MAX) hv_get_time_ref_count(current_tick);@@ -280,12 +280,8 @@ static bool __init hv_init_tsc_clocksource(void) if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) return false; - tsc_pg = vmalloc(PAGE_SIZE); - if (!tsc_pg) - return false; - hyperv_cs = &hyperv_cs_tsc; - phys_addr = page_to_phys(vmalloc_to_page(tsc_pg)); + phys_addr = virt_to_phys(&tsc_pg); /* * The Hyper-V TLFS specifies to preserve the value of reserved
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