After a kexec the logical processors and virtual processors already exist in the hypervisor because they were created by the previous kernel. Attempting to add them again causes either a BUG_ON or corrupted VP state leading to MCEs in the new kernel.
Add hv_lp_exists() to probe whether an LP is already present by calling HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME. When it succeeds the LP exists and we skip the add-LP and create-VP loops entirely. Also add hv_call_notify_all_processors_started() which informs the hypervisor that all processors are online. This is required after adding LPs (fresh boot) and is a no-op on kexec since we skip that path. Co-developed-by: Anirudh Rayabharam <[email protected]> Signed-off-by: Anirudh Rayabharam <[email protected]> Co-developed-by: Stanislav Kinsburskii <[email protected]> Signed-off-by: Stanislav Kinsburskii <[email protected]> Co-developed-by: Mukesh Rathor <[email protected]> Signed-off-by: Mukesh Rathor <[email protected]> Signed-off-by: Jork Loeser <[email protected]> --- arch/x86/kernel/cpu/mshyperv.c | 7 +++++ drivers/hv/hv_proc.c | 47 ++++++++++++++++++++++++++++++++++ include/asm-generic/mshyperv.h | 10 ++++++++ include/hyperv/hvgdk_mini.h | 1 + include/hyperv/hvhdk_mini.h | 12 +++++++++ 5 files changed, 77 insertions(+) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 235087456bdf..f653feea880b 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -429,6 +429,10 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus) } #ifdef CONFIG_X86_64 + /* If AP LPs exist, we are in a kexec'd kernel and VPs already exist */ + if (num_present_cpus() == 1 || hv_lp_exists(1)) + return; + for_each_present_cpu(i) { if (i == 0) continue; @@ -436,6 +440,9 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus) BUG_ON(ret); } + ret = hv_call_notify_all_processors_started(); + WARN_ON(ret); + for_each_present_cpu(i) { if (i == 0) continue; diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c index 5f4fd9c3231c..63a48e5a02c5 100644 --- a/drivers/hv/hv_proc.c +++ b/drivers/hv/hv_proc.c @@ -239,3 +239,50 @@ int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags) return ret; } EXPORT_SYMBOL_GPL(hv_call_create_vp); + +int hv_call_notify_all_processors_started(void) +{ + struct hv_input_notify_partition_event *input; + u64 status; + unsigned long irq_flags; + int ret = 0; + + local_irq_save(irq_flags); + input = *this_cpu_ptr(hyperv_pcpu_input_arg); + memset(input, 0, sizeof(*input)); + input->event = HV_PARTITION_ALL_LOGICAL_PROCESSORS_STARTED; + status = hv_do_hypercall(HVCALL_NOTIFY_PARTITION_EVENT, + input, NULL); + local_irq_restore(irq_flags); + + if (!hv_result_success(status)) { + hv_status_err(status, "\n"); + ret = hv_result_to_errno(status); + } + return ret; +} + +bool hv_lp_exists(u32 lp_index) +{ + struct hv_input_get_logical_processor_run_time *input; + struct hv_output_get_logical_processor_run_time *output; + unsigned long flags; + u64 status; + + local_irq_save(flags); + input = *this_cpu_ptr(hyperv_pcpu_input_arg); + output = *this_cpu_ptr(hyperv_pcpu_output_arg); + + input->lp_index = lp_index; + status = hv_do_hypercall(HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME, + input, output); + local_irq_restore(flags); + + if (!hv_result_success(status) && + hv_result(status) != HV_STATUS_INVALID_LP_INDEX) { + hv_status_err(status, "\n"); + BUG(); + } + + return hv_result_success(status); +} diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index d37b68238c97..bf601d67cecb 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -347,6 +347,8 @@ bool hv_result_needs_memory(u64 status); int hv_deposit_memory_node(int node, u64 partition_id, u64 status); int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id); +int hv_call_notify_all_processors_started(void); +bool hv_lp_exists(u32 lp_index); int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags); #else /* CONFIG_MSHV_ROOT */ @@ -366,6 +368,14 @@ static inline int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id) { return -EOPNOTSUPP; } +static inline int hv_call_notify_all_processors_started(void) +{ + return -EOPNOTSUPP; +} +static inline bool hv_lp_exists(u32 lp_index) +{ + return false; +} static inline int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags) { return -EOPNOTSUPP; diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h index 056ef7b6b360..f2598e186550 100644 --- a/include/hyperv/hvgdk_mini.h +++ b/include/hyperv/hvgdk_mini.h @@ -435,6 +435,7 @@ union hv_vp_assist_msr_contents { /* HV_REGISTER_VP_ASSIST_PAGE */ /* HV_CALL_CODE */ #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE 0x0002 #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST 0x0003 +#define HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME 0x0004 #define HVCALL_NOTIFY_LONG_SPIN_WAIT 0x0008 #define HVCALL_SEND_IPI 0x000b #define HVCALL_ENABLE_VP_VTL 0x000f diff --git a/include/hyperv/hvhdk_mini.h b/include/hyperv/hvhdk_mini.h index 091c03e26046..b4cb2fa26e9b 100644 --- a/include/hyperv/hvhdk_mini.h +++ b/include/hyperv/hvhdk_mini.h @@ -362,6 +362,7 @@ union hv_partition_event_input { enum hv_partition_event { HV_PARTITION_EVENT_ROOT_CRASHDUMP = 2, + HV_PARTITION_ALL_LOGICAL_PROCESSORS_STARTED = 4, }; struct hv_input_notify_partition_event { @@ -369,6 +370,17 @@ struct hv_input_notify_partition_event { union hv_partition_event_input input; } __packed; +struct hv_input_get_logical_processor_run_time { + u32 lp_index; +} __packed; + +struct hv_output_get_logical_processor_run_time { + u64 global_time; + u64 local_run_time; + u64 rsvdz0; + u64 hypervisor_time; +} __packed; + struct hv_lp_startup_status { u64 hv_status; u64 substatus1; -- 2.43.0
