From 90b20432aeb850ef84086a72893cd9411479d896 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 3 Mar 2017 14:21:42 +0100 Subject: [PATCH] x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the required support by adding hvclock_page VVAR. Signed-off-by: Vitaly Kuznetsov Cc: Stephen Hemminger Cc: Haiyang Zhang Cc: Dexuan Cui Cc: Andy Lutomirski Cc: devel@linuxdriverproject.org Cc: "K. Y. Srinivasan" Cc: virtualization@lists.linux-foundation.org Link: http://lkml.kernel.org/r/20170303132142.25595-4-vkuznets@redhat.com Signed-off-by: Thomas Gleixner --- arch/x86/entry/vdso/vclock_gettime.c | 24 ++++++++++++++++++++++++ arch/x86/entry/vdso/vdso-layout.lds.S | 3 ++- arch/x86/entry/vdso/vdso2c.c | 3 +++ arch/x86/entry/vdso/vma.c | 7 +++++++ arch/x86/hyperv/hv_init.c | 3 +++ arch/x86/include/asm/clocksource.h | 3 ++- arch/x86/include/asm/vdso.h | 1 + 7 files changed, 42 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 9d4d6e138311..fa8dbfcf7ed3 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -32,6 +33,11 @@ extern u8 pvclock_page __attribute__((visibility("hidden"))); #endif +#ifdef CONFIG_HYPERV_TSCPAGE +extern u8 hvclock_page + __attribute__((visibility("hidden"))); +#endif + #ifndef BUILD_VDSO32 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) @@ -141,6 +147,20 @@ static notrace u64 vread_pvclock(int *mode) return last; } #endif +#ifdef CONFIG_HYPERV_TSCPAGE +static notrace u64 vread_hvclock(int *mode) +{ + const struct ms_hyperv_tsc_page *tsc_pg = + (const struct ms_hyperv_tsc_page *)&hvclock_page; + u64 current_tick = hv_read_tsc_page(tsc_pg); + + if (current_tick != U64_MAX) + return current_tick; + + *mode = VCLOCK_NONE; + return 0; +} +#endif notrace static u64 vread_tsc(void) { @@ -172,6 +192,10 @@ notrace static inline u64 vgetsns(int *mode) #ifdef CONFIG_PARAVIRT_CLOCK else if (gtod->vclock_mode == VCLOCK_PVCLOCK) cycles = vread_pvclock(mode); +#endif +#ifdef CONFIG_HYPERV_TSCPAGE + else if (gtod->vclock_mode == VCLOCK_HVCLOCK) + cycles = vread_hvclock(mode); #endif else return 0; diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S index a708aa90b507..8ebb4b6454fe 100644 --- a/arch/x86/entry/vdso/vdso-layout.lds.S +++ b/arch/x86/entry/vdso/vdso-layout.lds.S @@ -25,7 +25,7 @@ SECTIONS * segment. */ - vvar_start = . - 2 * PAGE_SIZE; + vvar_start = . - 3 * PAGE_SIZE; vvar_page = vvar_start; /* Place all vvars at the offsets in asm/vvar.h. */ @@ -36,6 +36,7 @@ SECTIONS #undef EMIT_VVAR pvclock_page = vvar_start + PAGE_SIZE; + hvclock_page = vvar_start + 2 * PAGE_SIZE; . = SIZEOF_HEADERS; diff --git a/arch/x86/entry/vdso/vdso2c.c b/arch/x86/entry/vdso/vdso2c.c index 491020b2826d..0780a443a53b 100644 --- a/arch/x86/entry/vdso/vdso2c.c +++ b/arch/x86/entry/vdso/vdso2c.c @@ -74,6 +74,7 @@ enum { sym_vvar_page, sym_hpet_page, sym_pvclock_page, + sym_hvclock_page, sym_VDSO_FAKE_SECTION_TABLE_START, sym_VDSO_FAKE_SECTION_TABLE_END, }; @@ -82,6 +83,7 @@ const int special_pages[] = { sym_vvar_page, sym_hpet_page, sym_pvclock_page, + sym_hvclock_page, }; struct vdso_sym { @@ -94,6 +96,7 @@ struct vdso_sym required_syms[] = { [sym_vvar_page] = {"vvar_page", true}, [sym_hpet_page] = {"hpet_page", true}, [sym_pvclock_page] = {"pvclock_page", true}, + [sym_hvclock_page] = {"hvclock_page", true}, [sym_VDSO_FAKE_SECTION_TABLE_START] = { "VDSO_FAKE_SECTION_TABLE_START", false }, diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 226ca70dc6bd..faf80fdeeacc 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -22,6 +22,7 @@ #include #include #include +#include #if defined(CONFIG_X86_64) unsigned int __read_mostly vdso64_enabled = 1; @@ -121,6 +122,12 @@ static int vvar_fault(const struct vm_special_mapping *sm, vmf->address, __pa(pvti) >> PAGE_SHIFT); } + } else if (sym_offset == image->sym_hvclock_page) { + struct ms_hyperv_tsc_page *tsc_pg = hv_get_tsc_page(); + + if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK)) + ret = vm_insert_pfn(vma, vmf->address, + vmalloc_to_pfn(tsc_pg)); } if (ret == 0 || ret == -EBUSY) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 7f5152356a59..2b01421f7d0f 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -132,6 +132,9 @@ void hyperv_init(void) tsc_msr.guest_physical_address = vmalloc_to_pfn(tsc_pg); wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); + + hyperv_cs_tsc.archdata.vclock_mode = VCLOCK_HVCLOCK; + clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); return; } diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h index eae33c7170c8..47bea8cadbd0 100644 --- a/arch/x86/include/asm/clocksource.h +++ b/arch/x86/include/asm/clocksource.h @@ -6,7 +6,8 @@ #define VCLOCK_NONE 0 /* No vDSO clock available. */ #define VCLOCK_TSC 1 /* vDSO should use vread_tsc. */ #define VCLOCK_PVCLOCK 2 /* vDSO should use vread_pvclock. */ -#define VCLOCK_MAX 2 +#define VCLOCK_HVCLOCK 3 /* vDSO should use vread_hvclock. */ +#define VCLOCK_MAX 3 struct arch_clocksource_data { int vclock_mode; diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 2444189cbe28..bccdf4938ddf 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -20,6 +20,7 @@ struct vdso_image { long sym_vvar_page; long sym_hpet_page; long sym_pvclock_page; + long sym_hvclock_page; long sym_VDSO32_NOTE_MASK; long sym___kernel_sigreturn; long sym___kernel_rt_sigreturn; -- 2.20.1