From c445535c3efbfb8cb42d098e624d46ab149664b7 Mon Sep 17 00:00:00 2001 From: Ani Sinha Date: Tue, 13 Jul 2021 08:35:21 +0530 Subject: x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked unstable Marking TSC as unstable has a side effect of marking sched_clock as unstable when TSC is still being used as the sched_clock. This is not desirable. Hyper-V ultimately uses a paravirtualized clock source that provides a stable scheduler clock even on systems without TscInvariant CPU capability. Hence, mark_tsc_unstable() call should be called _after_ scheduler clock has been changed to the paravirtualized clocksource. This will prevent any unwanted manipulation of the sched_clock. Only TSC will be correctly marked as unstable. Signed-off-by: Ani Sinha Reviewed-by: Michael Kelley Tested-by: Michael Kelley Link: https://lore.kernel.org/r/20210713030522.1714803-1-ani@anisinha.ca Signed-off-by: Wei Liu --- arch/x86/kernel/cpu/mshyperv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index cc8f1773deca..8bd1c01c3310 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -375,8 +375,6 @@ static void __init ms_hyperv_init_platform(void) if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); - } else { - mark_tsc_unstable("running on Hyper-V"); } /* @@ -437,6 +435,13 @@ static void __init ms_hyperv_init_platform(void) /* Register Hyper-V specific clocksource */ hv_init_clocksource(); #endif + /* + * TSC should be marked as unstable only after Hyper-V + * clocksource has been initialized. This ensures that the + * stability of the sched_clock is not altered. + */ + if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT)) + mark_tsc_unstable("running on Hyper-V"); } static bool __init ms_hyperv_x2apic_available(void) -- cgit v1.2.3 From afca4d95dd7d7936d46a0ff02169cc40f534a6a3 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Wed, 14 Jul 2021 11:34:45 -0700 Subject: Drivers: hv: Make portions of Hyper-V init code be arch neutral The code to allocate and initialize the hv_vp_index array is architecture neutral. Similarly, the code to allocate and populate the hypercall input and output arg pages is architecture neutral. Move both sets of code out from arch/x86 and into utility functions in drivers/hv/hv_common.c that can be shared by Hyper-V initialization on ARM64. No functional changes. However, the allocation of the hypercall input and output arg pages is done differently so that the size is always the Hyper-V page size, even if not the same as the guest page size (such as with ARM64's 64K page size). Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1626287687-2045-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 91 +++----------------------- arch/x86/include/asm/mshyperv.h | 4 -- arch/x86/kernel/cpu/mshyperv.c | 3 - drivers/hv/hv_common.c | 138 ++++++++++++++++++++++++++++++++++++++++ include/asm-generic/mshyperv.h | 10 +++ 5 files changed, 158 insertions(+), 88 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 6952e219cba3..5cc0c0f30e75 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -39,48 +39,17 @@ EXPORT_SYMBOL_GPL(hv_hypercall_pg); /* Storage to save the hypercall page temporarily for hibernation */ static void *hv_hypercall_pg_saved; -u32 *hv_vp_index; -EXPORT_SYMBOL_GPL(hv_vp_index); - struct hv_vp_assist_page **hv_vp_assist_page; EXPORT_SYMBOL_GPL(hv_vp_assist_page); -void __percpu **hyperv_pcpu_input_arg; -EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg); - -void __percpu **hyperv_pcpu_output_arg; -EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg); - -u32 hv_max_vp_index; -EXPORT_SYMBOL_GPL(hv_max_vp_index); - static int hv_cpu_init(unsigned int cpu) { - u64 msr_vp_index; struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()]; - void **input_arg; - struct page *pg; - - /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */ - pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0); - if (unlikely(!pg)) - return -ENOMEM; - - input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); - *input_arg = page_address(pg); - if (hv_root_partition) { - void **output_arg; - - output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg); - *output_arg = page_address(pg + 1); - } - - msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX); - - hv_vp_index[smp_processor_id()] = msr_vp_index; + int ret; - if (msr_vp_index > hv_max_vp_index) - hv_max_vp_index = msr_vp_index; + ret = hv_common_cpu_init(cpu); + if (ret) + return ret; if (!hv_vp_assist_page) return 0; @@ -198,25 +167,8 @@ static int hv_cpu_die(unsigned int cpu) { struct hv_reenlightenment_control re_ctrl; unsigned int new_cpu; - unsigned long flags; - void **input_arg; - void *pg; - local_irq_save(flags); - input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); - pg = *input_arg; - *input_arg = NULL; - - if (hv_root_partition) { - void **output_arg; - - output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg); - *output_arg = NULL; - } - - local_irq_restore(flags); - - free_pages((unsigned long)pg, hv_root_partition ? 1 : 0); + hv_common_cpu_die(cpu); if (hv_vp_assist_page && hv_vp_assist_page[cpu]) wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0); @@ -368,7 +320,7 @@ void __init hyperv_init(void) { u64 guest_id, required_msrs; union hv_x64_msr_hypercall_contents hypercall_msr; - int cpuhp, i; + int cpuhp; if (x86_hyper_type != X86_HYPER_MS_HYPERV) return; @@ -380,36 +332,14 @@ void __init hyperv_init(void) if ((ms_hyperv.features & required_msrs) != required_msrs) return; - /* - * Allocate the per-CPU state for the hypercall input arg. - * If this allocation fails, we will not be able to setup - * (per-CPU) hypercall input page and thus this failure is - * fatal on Hyper-V. - */ - hyperv_pcpu_input_arg = alloc_percpu(void *); - - BUG_ON(hyperv_pcpu_input_arg == NULL); - - /* Allocate the per-CPU state for output arg for root */ - if (hv_root_partition) { - hyperv_pcpu_output_arg = alloc_percpu(void *); - BUG_ON(hyperv_pcpu_output_arg == NULL); - } - - /* Allocate percpu VP index */ - hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index), - GFP_KERNEL); - if (!hv_vp_index) + if (hv_common_init()) return; - for (i = 0; i < num_possible_cpus(); i++) - hv_vp_index[i] = VP_INVAL; - hv_vp_assist_page = kcalloc(num_possible_cpus(), sizeof(*hv_vp_assist_page), GFP_KERNEL); if (!hv_vp_assist_page) { ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED; - goto free_vp_index; + goto common_free; } cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", @@ -507,9 +437,8 @@ remove_cpuhp_state: free_vp_assist_page: kfree(hv_vp_assist_page); hv_vp_assist_page = NULL; -free_vp_index: - kfree(hv_vp_index); - hv_vp_index = NULL; +common_free: + hv_common_free(); } /* diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 67ff0d637e55..adccbc209169 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -36,8 +36,6 @@ void hyperv_vector_handler(struct pt_regs *regs); extern int hyperv_init_cpuhp; extern void *hv_hypercall_pg; -extern void __percpu **hyperv_pcpu_input_arg; -extern void __percpu **hyperv_pcpu_output_arg; extern u64 hv_current_partition_id; @@ -170,8 +168,6 @@ int hyperv_fill_flush_guest_mapping_list( struct hv_guest_mapping_flush_list *flush, u64 start_gfn, u64 end_gfn); -extern bool hv_root_partition; - #ifdef CONFIG_X86_64 void hv_apic_init(void); void __init hv_init_spinlocks(void); diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 8bd1c01c3310..40d3656d5461 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -36,10 +36,7 @@ /* Is Linux running as the root partition? */ bool hv_root_partition; -EXPORT_SYMBOL_GPL(hv_root_partition); - struct ms_hyperv_info ms_hyperv; -EXPORT_SYMBOL_GPL(ms_hyperv); #if IS_ENABLED(CONFIG_HYPERV) static void (*vmbus_handler)(void); diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 7f42da98d377..e836002bc0ce 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -15,9 +15,147 @@ #include #include #include +#include +#include #include #include +/* + * hv_root_partition and ms_hyperv are defined here with other Hyper-V + * specific globals so they are shared across all architectures and are + * built only when CONFIG_HYPERV is defined. But on x86, + * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not + * defined, and it uses these two variables. So mark them as __weak + * here, allowing for an overriding definition in the module containing + * ms_hyperv_init_platform(). + */ +bool __weak hv_root_partition; +EXPORT_SYMBOL_GPL(hv_root_partition); + +struct ms_hyperv_info __weak ms_hyperv; +EXPORT_SYMBOL_GPL(ms_hyperv); + +u32 *hv_vp_index; +EXPORT_SYMBOL_GPL(hv_vp_index); + +u32 hv_max_vp_index; +EXPORT_SYMBOL_GPL(hv_max_vp_index); + +void __percpu **hyperv_pcpu_input_arg; +EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg); + +void __percpu **hyperv_pcpu_output_arg; +EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg); + +/* + * Hyper-V specific initialization and shutdown code that is + * common across all architectures. Called from architecture + * specific initialization functions. + */ + +void __init hv_common_free(void) +{ + kfree(hv_vp_index); + hv_vp_index = NULL; + + free_percpu(hyperv_pcpu_output_arg); + hyperv_pcpu_output_arg = NULL; + + free_percpu(hyperv_pcpu_input_arg); + hyperv_pcpu_input_arg = NULL; +} + +int __init hv_common_init(void) +{ + int i; + + /* + * Allocate the per-CPU state for the hypercall input arg. + * If this allocation fails, we will not be able to setup + * (per-CPU) hypercall input page and thus this failure is + * fatal on Hyper-V. + */ + hyperv_pcpu_input_arg = alloc_percpu(void *); + BUG_ON(!hyperv_pcpu_input_arg); + + /* Allocate the per-CPU state for output arg for root */ + if (hv_root_partition) { + hyperv_pcpu_output_arg = alloc_percpu(void *); + BUG_ON(!hyperv_pcpu_output_arg); + } + + hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index), + GFP_KERNEL); + if (!hv_vp_index) { + hv_common_free(); + return -ENOMEM; + } + + for (i = 0; i < num_possible_cpus(); i++) + hv_vp_index[i] = VP_INVAL; + + return 0; +} + +/* + * Hyper-V specific initialization and die code for + * individual CPUs that is common across all architectures. + * Called by the CPU hotplug mechanism. + */ + +int hv_common_cpu_init(unsigned int cpu) +{ + void **inputarg, **outputarg; + u64 msr_vp_index; + gfp_t flags; + int pgcount = hv_root_partition ? 2 : 1; + + /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */ + flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL; + + inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); + *inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags); + if (!(*inputarg)) + return -ENOMEM; + + if (hv_root_partition) { + outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg); + *outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE; + } + + msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX); + + hv_vp_index[cpu] = msr_vp_index; + + if (msr_vp_index > hv_max_vp_index) + hv_max_vp_index = msr_vp_index; + + return 0; +} + +int hv_common_cpu_die(unsigned int cpu) +{ + unsigned long flags; + void **inputarg, **outputarg; + void *mem; + + local_irq_save(flags); + + inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg); + mem = *inputarg; + *inputarg = NULL; + + if (hv_root_partition) { + outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg); + *outputarg = NULL; + } + + local_irq_restore(flags); + + kfree(mem); + + return 0; +} /* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */ bool hv_query_ext_cap(u64 cap_query) diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 2ccb40670552..60cdff3e2252 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -39,6 +39,9 @@ struct ms_hyperv_info { }; extern struct ms_hyperv_info ms_hyperv; +extern void __percpu **hyperv_pcpu_input_arg; +extern void __percpu **hyperv_pcpu_output_arg; + extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr); extern u64 hv_do_fast_hypercall8(u16 control, u64 input8); @@ -152,6 +155,8 @@ void hv_remove_crash_handler(void); extern int vmbus_interrupt; extern int vmbus_irq; +extern bool hv_root_partition; + #if IS_ENABLED(CONFIG_HYPERV) /* * Hypervisor's notion of virtual processor ID is different from @@ -165,6 +170,11 @@ extern u32 hv_max_vp_index; /* Sentinel value for an uninitialized entry in hv_vp_index array */ #define VP_INVAL U32_MAX +int __init hv_common_init(void); +void __init hv_common_free(void); +int hv_common_cpu_init(unsigned int cpu); +int hv_common_cpu_die(unsigned int cpu); + void *hv_alloc_hyperv_page(void); void *hv_alloc_hyperv_zeroed_page(void); void hv_free_hyperv_page(unsigned long addr); -- cgit v1.2.3 From 9d7cf2c9675838c12cd5cf5a4ebe2ba41bd78a44 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Wed, 14 Jul 2021 11:34:46 -0700 Subject: Drivers: hv: Add arch independent default functions for some Hyper-V handlers Architecture independent Hyper-V code calls various arch-specific handlers when needed. To aid in supporting multiple architectures, provide weak defaults that can be overridden by arch-specific implementations where appropriate. But when arch-specific overrides aren't needed or haven't been implemented yet for a particular architecture, these stubs reduce the amount of clutter under arch/. No functional change. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1626287687-2045-3-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 2 -- arch/x86/kernel/cpu/mshyperv.c | 6 ------ drivers/hv/hv_common.c | 49 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 8 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 5cc0c0f30e75..e87a0293b705 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -468,7 +468,6 @@ void hyperv_cleanup(void) hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); } -EXPORT_SYMBOL_GPL(hyperv_cleanup); void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) { @@ -542,4 +541,3 @@ bool hv_is_isolation_supported(void) { return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; } -EXPORT_SYMBOL_GPL(hv_is_isolation_supported); diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 40d3656d5461..0b647965e039 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -62,14 +62,12 @@ void hv_setup_vmbus_handler(void (*handler)(void)) { vmbus_handler = handler; } -EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler); void hv_remove_vmbus_handler(void) { /* We have no way to deallocate the interrupt gate */ vmbus_handler = NULL; } -EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler); /* * Routines to do per-architecture handling of stimer0 @@ -104,25 +102,21 @@ void hv_setup_kexec_handler(void (*handler)(void)) { hv_kexec_handler = handler; } -EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); void hv_remove_kexec_handler(void) { hv_kexec_handler = NULL; } -EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) { hv_crash_handler = handler; } -EXPORT_SYMBOL_GPL(hv_setup_crash_handler); void hv_remove_crash_handler(void) { hv_crash_handler = NULL; } -EXPORT_SYMBOL_GPL(hv_remove_crash_handler); #ifdef CONFIG_KEXEC_CORE static void hv_machine_shutdown(void) diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index e836002bc0ce..fe333f410d1d 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -202,3 +203,51 @@ bool hv_query_ext_cap(u64 cap_query) return hv_extended_cap & cap_query; } EXPORT_SYMBOL_GPL(hv_query_ext_cap); + +/* These __weak functions provide default "no-op" behavior and + * may be overridden by architecture specific versions. Architectures + * for which the default "no-op" behavior is sufficient can leave + * them unimplemented and not be cluttered with a bunch of stub + * functions in arch-specific code. + */ + +bool __weak hv_is_isolation_supported(void) +{ + return false; +} +EXPORT_SYMBOL_GPL(hv_is_isolation_supported); + +void __weak hv_setup_vmbus_handler(void (*handler)(void)) +{ +} +EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler); + +void __weak hv_remove_vmbus_handler(void) +{ +} +EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler); + +void __weak hv_setup_kexec_handler(void (*handler)(void)) +{ +} +EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); + +void __weak hv_remove_kexec_handler(void) +{ +} +EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); + +void __weak hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) +{ +} +EXPORT_SYMBOL_GPL(hv_setup_crash_handler); + +void __weak hv_remove_crash_handler(void) +{ +} +EXPORT_SYMBOL_GPL(hv_remove_crash_handler); + +void __weak hyperv_cleanup(void) +{ +} +EXPORT_SYMBOL_GPL(hyperv_cleanup); -- cgit v1.2.3 From 6dc77fa5ac2cf26f846a51492dbe42526e26d0f2 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Wed, 14 Jul 2021 11:34:47 -0700 Subject: Drivers: hv: Move Hyper-V misc functionality to arch-neutral code The check for whether hibernation is possible, and the enabling of Hyper-V panic notification during kexec, are both architecture neutral. Move the code from under arch/x86 and into drivers/hv/hv_common.c where it can also be used for ARM64. No functional change. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1626287687-2045-4-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 8 +------- arch/x86/kernel/cpu/mshyperv.c | 11 ----------- drivers/hv/hv_common.c | 18 ++++++++++++++++++ 3 files changed, 19 insertions(+), 18 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index e87a0293b705..6f247e7e07eb 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -7,10 +7,10 @@ * Author : K. Y. Srinivasan */ -#include #include #include #include +#include #include #include #include @@ -523,12 +523,6 @@ bool hv_is_hyperv_initialized(void) } EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); -bool hv_is_hibernation_supported(void) -{ - return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4); -} -EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); - enum hv_isolation_type hv_get_isolation_type(void) { if (!(ms_hyperv.priv_high & HV_ISOLATION)) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 0b647965e039..30baae031481 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -17,7 +17,6 @@ #include #include #include -#include #include #include #include @@ -326,16 +325,6 @@ static void __init ms_hyperv_init_platform(void) ms_hyperv.nested_features); } - /* - * Hyper-V expects to get crash register data or kmsg when - * crash enlightment is available and system crashes. Set - * crash_kexec_post_notifiers to be true to make sure that - * calling crash enlightment interface before running kdump - * kernel. - */ - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) - crash_kexec_post_notifiers = true; - #ifdef CONFIG_X86_LOCAL_APIC if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index fe333f410d1d..46658de78050 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -13,9 +13,11 @@ */ #include +#include #include #include #include +#include #include #include #include @@ -70,6 +72,16 @@ int __init hv_common_init(void) { int i; + /* + * Hyper-V expects to get crash register data or kmsg when + * crash enlightment is available and system crashes. Set + * crash_kexec_post_notifiers to be true to make sure that + * calling crash enlightment interface before running kdump + * kernel. + */ + if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) + crash_kexec_post_notifiers = true; + /* * Allocate the per-CPU state for the hypercall input arg. * If this allocation fails, we will not be able to setup @@ -204,6 +216,12 @@ bool hv_query_ext_cap(u64 cap_query) } EXPORT_SYMBOL_GPL(hv_query_ext_cap); +bool hv_is_hibernation_supported(void) +{ + return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4); +} +EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); + /* These __weak functions provide default "no-op" behavior and * may be overridden by architecture specific versions. Architectures * for which the default "no-op" behavior is sufficient can leave -- cgit v1.2.3 From 5f92b45c3b67e3d222caf10e2eb898af31756b67 Mon Sep 17 00:00:00 2001 From: Ani Sinha Date: Fri, 16 Jul 2021 19:02:45 +0530 Subject: x86/hyperv: add comment describing TSC_INVARIANT_CONTROL MSR setting bit 0 Commit dce7cd62754b5 ("x86/hyperv: Allow guests to enable InvariantTSC") added the support for HV_X64_MSR_TSC_INVARIANT_CONTROL. Setting bit 0 of this synthetic MSR will allow hyper-v guests to report invariant TSC CPU feature through CPUID. This comment adds this explanation to the code and mentions where the Intel's generic platform init code reads this feature bit from CPUID. The comment will help developers understand how the two parts of the initialization (hyperV specific and non-hyperV specific generic hw init) are related. Signed-off-by: Ani Sinha Reviewed-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210716133245.3272672-1-ani@anisinha.ca Signed-off-by: Wei Liu --- arch/x86/kernel/cpu/mshyperv.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 30baae031481..6b5835a087a3 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -353,6 +353,15 @@ static void __init ms_hyperv_init_platform(void) machine_ops.crash_shutdown = hv_machine_crash_shutdown; #endif if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { + /* + * Writing to synthetic MSR 0x40000118 updates/changes the + * guest visible CPUIDs. Setting bit 0 of this MSR enables + * guests to report invariant TSC feature through CPUID + * instruction, CPUID 0x800000007/EDX, bit 8. See code in + * early_init_intel() where this bit is examined. The + * setting of this MSR bit should happen before init_intel() + * is called. + */ wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); } -- cgit v1.2.3