From 062a5c4260cdb734a4727230c58e38accf413315 Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Mon, 13 Dec 2021 02:14:04 -0500 Subject: hyper-v: Enable swiotlb bounce buffer for Isolation VM hyperv Isolation VM requires bounce buffer support to copy data from/to encrypted memory and so enable swiotlb force mode to use swiotlb bounce buffer for DMA transaction. In Isolation VM with AMD SEV, the bounce buffer needs to be accessed via extra address space which is above shared_gpa_boundary (E.G 39 bit address line) reported by Hyper-V CPUID ISOLATION_CONFIG. The access physical address will be original physical address + shared_gpa_boundary. The shared_gpa_boundary in the AMD SEV SNP spec is called virtual top of memory(vTOM). Memory addresses below vTOM are automatically treated as private while memory above vTOM is treated as shared. Swiotlb bounce buffer code calls set_memory_decrypted() to mark bounce buffer visible to host and map it in extra address space via memremap. Populate the shared_gpa_boundary (vTOM) via swiotlb_unencrypted_base variable. The map function memremap() can't work in the early place (e.g ms_hyperv_init_platform()) and so call swiotlb_update_mem_ attributes() in the hyperv_init(). Signed-off-by: Tianyu Lan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20211213071407.314309-4-ltykernel@gmail.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 96eb7db31c8e..559b6954fee6 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -28,6 +28,7 @@ #include #include #include +#include int hyperv_init_cpuhp; u64 hv_current_partition_id = ~0ull; @@ -498,6 +499,17 @@ void __init hyperv_init(void) /* Query the VMs extended capability once, so that it can be cached. */ hv_query_ext_cap(0); + +#ifdef CONFIG_SWIOTLB + /* + * Swiotlb bounce buffer needs to be mapped in extra address + * space. Map function doesn't work in the early place and so + * call swiotlb_update_mem_attributes() here. + */ + if (hv_is_isolation_supported()) + swiotlb_update_mem_attributes(); +#endif + return; clean_guest_os_id: -- cgit v1.2.3 From 846da38de0e8224f2f94b885125cf1fd2d7b0d39 Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Mon, 13 Dec 2021 02:14:06 -0500 Subject: net: netvsc: Add Isolation VM support for netvsc driver In Isolation VM, all shared memory with host needs to mark visible to host via hvcall. vmbus_establish_gpadl() has already done it for netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_ pagebuffer() stills need to be handled. Use DMA API to map/umap these memory during sending/receiving packet and Hyper-V swiotlb bounce buffer dma address will be returned. The swiotlb bounce buffer has been masked to be visible to host during boot up. rx/tx ring buffer is allocated via vzalloc() and they need to be mapped into unencrypted address space(above vTOM) before sharing with host and accessing. Add hv_map/unmap_memory() to map/umap rx /tx ring buffer. Signed-off-by: Tianyu Lan Reviewed-by: Haiyang Zhang Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20211213071407.314309-6-ltykernel@gmail.com Signed-off-by: Wei Liu --- arch/x86/hyperv/ivm.c | 28 ++++++++ drivers/hv/hv_common.c | 11 +++ drivers/net/hyperv/hyperv_net.h | 5 ++ drivers/net/hyperv/netvsc.c | 136 +++++++++++++++++++++++++++++++++++++- drivers/net/hyperv/netvsc_drv.c | 1 + drivers/net/hyperv/rndis_filter.c | 2 + include/asm-generic/mshyperv.h | 2 + include/linux/hyperv.h | 5 ++ 8 files changed, 187 insertions(+), 3 deletions(-) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c index 69c7a57f3307..2b994117581e 100644 --- a/arch/x86/hyperv/ivm.c +++ b/arch/x86/hyperv/ivm.c @@ -287,3 +287,31 @@ int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visibl kfree(pfn_array); return ret; } + +/* + * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM. + */ +void *hv_map_memory(void *addr, unsigned long size) +{ + unsigned long *pfns = kcalloc(size / PAGE_SIZE, + sizeof(unsigned long), GFP_KERNEL); + void *vaddr; + int i; + + if (!pfns) + return NULL; + + for (i = 0; i < size / PAGE_SIZE; i++) + pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) + + (ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT); + + vaddr = vmap_pfn(pfns, size / PAGE_SIZE, PAGE_KERNEL_IO); + kfree(pfns); + + return vaddr; +} + +void hv_unmap_memory(void *addr) +{ + vunmap(addr); +} diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 7be173a99f27..3c5cb1f70319 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -295,3 +295,14 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s return HV_STATUS_INVALID_PARAMETER; } EXPORT_SYMBOL_GPL(hv_ghcb_hypercall); + +void __weak *hv_map_memory(void *addr, unsigned long size) +{ + return NULL; +} +EXPORT_SYMBOL_GPL(hv_map_memory); + +void __weak hv_unmap_memory(void *addr) +{ +} +EXPORT_SYMBOL_GPL(hv_unmap_memory); diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index 315278a7cf88..cf69da0e296c 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -164,6 +164,7 @@ struct hv_netvsc_packet { u32 total_bytes; u32 send_buf_index; u32 total_data_buflen; + struct hv_dma_range *dma_range; }; #define NETVSC_HASH_KEYLEN 40 @@ -1074,6 +1075,7 @@ struct netvsc_device { /* Receive buffer allocated by us but manages by NetVSP */ void *recv_buf; + void *recv_original_buf; u32 recv_buf_size; /* allocated bytes */ struct vmbus_gpadl recv_buf_gpadl_handle; u32 recv_section_cnt; @@ -1082,6 +1084,7 @@ struct netvsc_device { /* Send buffer allocated by us */ void *send_buf; + void *send_original_buf; u32 send_buf_size; struct vmbus_gpadl send_buf_gpadl_handle; u32 send_section_cnt; @@ -1731,4 +1734,6 @@ struct rndis_message { #define RETRY_US_HI 10000 #define RETRY_MAX 2000 /* >10 sec */ +void netvsc_dma_unmap(struct hv_device *hv_dev, + struct hv_netvsc_packet *packet); #endif /* _HYPERV_NET_H */ diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index 396bc1c204e6..ea2d867121d5 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -153,8 +153,21 @@ static void free_netvsc_device(struct rcu_head *head) int i; kfree(nvdev->extension); - vfree(nvdev->recv_buf); - vfree(nvdev->send_buf); + + if (nvdev->recv_original_buf) { + hv_unmap_memory(nvdev->recv_buf); + vfree(nvdev->recv_original_buf); + } else { + vfree(nvdev->recv_buf); + } + + if (nvdev->send_original_buf) { + hv_unmap_memory(nvdev->send_buf); + vfree(nvdev->send_original_buf); + } else { + vfree(nvdev->send_buf); + } + kfree(nvdev->send_section_map); for (i = 0; i < VRSS_CHANNEL_MAX; i++) { @@ -338,6 +351,7 @@ static int netvsc_init_buf(struct hv_device *device, unsigned int buf_size; size_t map_words; int i, ret = 0; + void *vaddr; /* Get receive buffer area. */ buf_size = device_info->recv_sections * device_info->recv_section_size; @@ -373,6 +387,17 @@ static int netvsc_init_buf(struct hv_device *device, goto cleanup; } + if (hv_isolation_type_snp()) { + vaddr = hv_map_memory(net_device->recv_buf, buf_size); + if (!vaddr) { + ret = -ENOMEM; + goto cleanup; + } + + net_device->recv_original_buf = net_device->recv_buf; + net_device->recv_buf = vaddr; + } + /* Notify the NetVsp of the gpadl handle */ init_packet = &net_device->channel_init_pkt; memset(init_packet, 0, sizeof(struct nvsp_message)); @@ -476,6 +501,17 @@ static int netvsc_init_buf(struct hv_device *device, goto cleanup; } + if (hv_isolation_type_snp()) { + vaddr = hv_map_memory(net_device->send_buf, buf_size); + if (!vaddr) { + ret = -ENOMEM; + goto cleanup; + } + + net_device->send_original_buf = net_device->send_buf; + net_device->send_buf = vaddr; + } + /* Notify the NetVsp of the gpadl handle */ init_packet = &net_device->channel_init_pkt; memset(init_packet, 0, sizeof(struct nvsp_message)); @@ -766,7 +802,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev, /* Notify the layer above us */ if (likely(skb)) { - const struct hv_netvsc_packet *packet + struct hv_netvsc_packet *packet = (struct hv_netvsc_packet *)skb->cb; u32 send_index = packet->send_buf_index; struct netvsc_stats *tx_stats; @@ -782,6 +818,7 @@ static void netvsc_send_tx_complete(struct net_device *ndev, tx_stats->bytes += packet->total_bytes; u64_stats_update_end(&tx_stats->syncp); + netvsc_dma_unmap(ndev_ctx->device_ctx, packet); napi_consume_skb(skb, budget); } @@ -946,6 +983,88 @@ static void netvsc_copy_to_send_buf(struct netvsc_device *net_device, memset(dest, 0, padding); } +void netvsc_dma_unmap(struct hv_device *hv_dev, + struct hv_netvsc_packet *packet) +{ + u32 page_count = packet->cp_partial ? + packet->page_buf_cnt - packet->rmsg_pgcnt : + packet->page_buf_cnt; + int i; + + if (!hv_is_isolation_supported()) + return; + + if (!packet->dma_range) + return; + + for (i = 0; i < page_count; i++) + dma_unmap_single(&hv_dev->device, packet->dma_range[i].dma, + packet->dma_range[i].mapping_size, + DMA_TO_DEVICE); + + kfree(packet->dma_range); +} + +/* netvsc_dma_map - Map swiotlb bounce buffer with data page of + * packet sent by vmbus_sendpacket_pagebuffer() in the Isolation + * VM. + * + * In isolation VM, netvsc send buffer has been marked visible to + * host and so the data copied to send buffer doesn't need to use + * bounce buffer. The data pages handled by vmbus_sendpacket_pagebuffer() + * may not be copied to send buffer and so these pages need to be + * mapped with swiotlb bounce buffer. netvsc_dma_map() is to do + * that. The pfns in the struct hv_page_buffer need to be converted + * to bounce buffer's pfn. The loop here is necessary because the + * entries in the page buffer array are not necessarily full + * pages of data. Each entry in the array has a separate offset and + * len that may be non-zero, even for entries in the middle of the + * array. And the entries are not physically contiguous. So each + * entry must be individually mapped rather than as a contiguous unit. + * So not use dma_map_sg() here. + */ +static int netvsc_dma_map(struct hv_device *hv_dev, + struct hv_netvsc_packet *packet, + struct hv_page_buffer *pb) +{ + u32 page_count = packet->cp_partial ? + packet->page_buf_cnt - packet->rmsg_pgcnt : + packet->page_buf_cnt; + dma_addr_t dma; + int i; + + if (!hv_is_isolation_supported()) + return 0; + + packet->dma_range = kcalloc(page_count, + sizeof(*packet->dma_range), + GFP_KERNEL); + if (!packet->dma_range) + return -ENOMEM; + + for (i = 0; i < page_count; i++) { + char *src = phys_to_virt((pb[i].pfn << HV_HYP_PAGE_SHIFT) + + pb[i].offset); + u32 len = pb[i].len; + + dma = dma_map_single(&hv_dev->device, src, len, + DMA_TO_DEVICE); + if (dma_mapping_error(&hv_dev->device, dma)) { + kfree(packet->dma_range); + return -ENOMEM; + } + + /* pb[].offset and pb[].len are not changed during dma mapping + * and so not reassign. + */ + packet->dma_range[i].dma = dma; + packet->dma_range[i].mapping_size = len; + pb[i].pfn = dma >> HV_HYP_PAGE_SHIFT; + } + + return 0; +} + static inline int netvsc_send_pkt( struct hv_device *device, struct hv_netvsc_packet *packet, @@ -986,14 +1105,24 @@ static inline int netvsc_send_pkt( trace_nvsp_send_pkt(ndev, out_channel, rpkt); + packet->dma_range = NULL; if (packet->page_buf_cnt) { if (packet->cp_partial) pb += packet->rmsg_pgcnt; + ret = netvsc_dma_map(ndev_ctx->device_ctx, packet, pb); + if (ret) { + ret = -EAGAIN; + goto exit; + } + ret = vmbus_sendpacket_pagebuffer(out_channel, pb, packet->page_buf_cnt, &nvmsg, sizeof(nvmsg), req_id); + + if (ret) + netvsc_dma_unmap(ndev_ctx->device_ctx, packet); } else { ret = vmbus_sendpacket(out_channel, &nvmsg, sizeof(nvmsg), @@ -1001,6 +1130,7 @@ static inline int netvsc_send_pkt( VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); } +exit: if (ret == 0) { atomic_inc_return(&nvchan->queue_sends); diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 7e66ae1d2a59..17958533bf30 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -2512,6 +2512,7 @@ static int netvsc_probe(struct hv_device *dev, net->netdev_ops = &device_ops; net->ethtool_ops = ðtool_ops; SET_NETDEV_DEV(net, &dev->device); + dma_set_min_align_mask(&dev->device, HV_HYP_PAGE_SIZE - 1); /* We always need headroom for rndis header */ net->needed_headroom = RNDIS_AND_PPI_SIZE; diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c index f6c9c2a670f9..448fcc325ed7 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -361,6 +361,8 @@ static void rndis_filter_receive_response(struct net_device *ndev, } } + netvsc_dma_unmap(((struct net_device_context *) + netdev_priv(ndev))->device_ctx, &request->pkt); complete(&request->wait_event); } else { netdev_err(ndev, diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 3e2248ac328e..94e73ba129c5 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -269,6 +269,8 @@ bool hv_isolation_type_snp(void); u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size); void hyperv_cleanup(void); bool hv_query_ext_cap(u64 cap_query); +void *hv_map_memory(void *addr, unsigned long size); +void hv_unmap_memory(void *addr); #else /* CONFIG_HYPERV */ static inline bool hv_is_hyperv_initialized(void) { return false; } static inline bool hv_is_hibernation_supported(void) { return false; } diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 650a0574b746..f565a8938836 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1584,6 +1584,11 @@ struct hyperv_service_callback { void (*callback)(void *context); }; +struct hv_dma_range { + dma_addr_t dma; + u32 mapping_size; +}; + #define MAX_SRV_VER 0x7ffffff extern bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf, u32 buflen, const int *fw_version, int fw_vercnt, -- cgit v1.2.3 From e1878402ab2dca12d1426f2fea39757943f3332c Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Mon, 27 Dec 2021 19:31:55 -0800 Subject: x86/hyperv: Fix definition of hv_ghcb_pg variable The percpu variable hv_ghcb_pg is incorrectly defined. The __percpu qualifier should be associated with the union hv_ghcb * (i.e., a pointer), not with the target of the pointer. This distinction makes no difference to gcc and the generated code, but sparse correctly complains. Fix the definition in the interest of general correctness in addition to making sparse happy. No functional change. Fixes: 0cc4f6d9f0b9 ("x86/hyperv: Initialize GHCB page in Isolation VM") Reported-by: kernel test robot Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1640662315-22260-2-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 2 +- arch/x86/include/asm/mshyperv.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 559b6954fee6..8b392b6b7b93 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -37,7 +37,7 @@ EXPORT_SYMBOL_GPL(hv_current_partition_id); void *hv_hypercall_pg; EXPORT_SYMBOL_GPL(hv_hypercall_pg); -union hv_ghcb __percpu **hv_ghcb_pg; +union hv_ghcb * __percpu *hv_ghcb_pg; /* Storage to save the hypercall page temporarily for hibernation */ static void *hv_hypercall_pg_saved; diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index da3972fe5a7a..498317df89b0 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -30,7 +30,7 @@ extern void *hv_hypercall_pg; extern u64 hv_current_partition_id; -extern union hv_ghcb __percpu **hv_ghcb_pg; +extern union hv_ghcb * __percpu *hv_ghcb_pg; 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); -- cgit v1.2.3 From 51500b71d500f251037ed339047a4d9e7d7e295b Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 6 Jan 2022 10:46:11 +0100 Subject: x86/hyperv: Properly deal with empty cpumasks in hyperv_flush_tlb_multi() KASAN detected the following issue: BUG: KASAN: slab-out-of-bounds in hyperv_flush_tlb_multi+0xf88/0x1060 Read of size 4 at addr ffff8880011ccbc0 by task kcompactd0/33 CPU: 1 PID: 33 Comm: kcompactd0 Not tainted 5.14.0-39.el9.x86_64+debug #1 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019 Call Trace: dump_stack_lvl+0x57/0x7d print_address_description.constprop.0+0x1f/0x140 ? hyperv_flush_tlb_multi+0xf88/0x1060 __kasan_report.cold+0x7f/0x11e ? hyperv_flush_tlb_multi+0xf88/0x1060 kasan_report+0x38/0x50 hyperv_flush_tlb_multi+0xf88/0x1060 flush_tlb_mm_range+0x1b1/0x200 ptep_clear_flush+0x10e/0x150 ... Allocated by task 0: kasan_save_stack+0x1b/0x40 __kasan_kmalloc+0x7c/0x90 hv_common_init+0xae/0x115 hyperv_init+0x97/0x501 apic_intr_mode_init+0xb3/0x1e0 x86_late_time_init+0x92/0xa2 start_kernel+0x338/0x3eb secondary_startup_64_no_verify+0xc2/0xcb The buggy address belongs to the object at ffff8880011cc800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 960 bytes inside of 1024-byte region [ffff8880011cc800, ffff8880011ccc00) 'hyperv_flush_tlb_multi+0xf88/0x1060' points to hv_cpu_number_to_vp_number() and '960 bytes' means we're trying to get VP_INDEX for CPU#240. 'nr_cpus' here is exactly 240 so we're trying to access past hv_vp_index's last element. This can (and will) happen when 'cpus' mask is empty and cpumask_last() will return '>=nr_cpus'. Commit ad0a6bad4475 ("x86/hyperv: check cpu mask after interrupt has been disabled") tried to deal with empty cpumask situation but apparently didn't fully fix the issue. 'cpus' cpumask which is passed to hyperv_flush_tlb_multi() is 'mm_cpumask(mm)' (which is '&mm->cpu_bitmap'). This mask changes every time the particular mm is scheduled/unscheduled on some CPU (see switch_mm_irqs_off()), disabling IRQs on the CPU which is performing remote TLB flush has zero influence on whether the particular process can get scheduled/unscheduled on _other_ CPUs so e.g. in the case where the mm was scheduled on one other CPU and got unscheduled during hyperv_flush_tlb_multi()'s execution will lead to cpumask becoming empty. It doesn't seem that there's a good way to protect 'mm_cpumask(mm)' from changing during hyperv_flush_tlb_multi()'s execution. It would be possible to copy it in the very beginning of the function but this is a waste. It seems we can deal with changing cpumask just fine. When 'cpus' cpumask changes during hyperv_flush_tlb_multi()'s execution, there are two possible issues: - 'Under-flushing': we will not flush TLB on a CPU which got added to the mask while hyperv_flush_tlb_multi() was already running. This is not a problem as this is equal to mm getting scheduled on that CPU right after TLB flush. - 'Over-flushing': we may flush TLB on a CPU which is already cleared from the mask. First, extra TLB flush preserves correctness. Second, Hyper-V's TLB flush hypercall takes 'mm->pgd' argument so Hyper-V may avoid the flush if CR3 doesn't match. Fix the immediate issue with cpumask_last()/hv_cpu_number_to_vp_number() and remove the pointless cpumask_empty() check from the beginning of the function as it really doesn't protect anything. Also, avoid the hypercall altogether when 'flush->processor_mask' ends up being empty. Fixes: ad0a6bad4475 ("x86/hyperv: check cpu mask after interrupt has been disabled") Signed-off-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220106094611.1404218-1-vkuznets@redhat.com Signed-off-by: Wei Liu --- arch/x86/hyperv/mmu.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'arch/x86/hyperv') diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c index bd13736d0c05..0ad2378fe6ad 100644 --- a/arch/x86/hyperv/mmu.c +++ b/arch/x86/hyperv/mmu.c @@ -68,15 +68,6 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus, local_irq_save(flags); - /* - * Only check the mask _after_ interrupt has been disabled to avoid the - * mask changing under our feet. - */ - if (cpumask_empty(cpus)) { - local_irq_restore(flags); - return; - } - flush_pcpu = (struct hv_tlb_flush **) this_cpu_ptr(hyperv_pcpu_input_arg); @@ -115,7 +106,9 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus, * must. We will also check all VP numbers when walking the * supplied CPU set to remain correct in all cases. */ - if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64) + cpu = cpumask_last(cpus); + + if (cpu < nr_cpumask_bits && hv_cpu_number_to_vp_number(cpu) >= 64) goto do_ex_hypercall; for_each_cpu(cpu, cpus) { @@ -131,6 +124,12 @@ static void hyperv_flush_tlb_multi(const struct cpumask *cpus, __set_bit(vcpu, (unsigned long *) &flush->processor_mask); } + + /* nothing to flush if 'processor_mask' ends up being empty */ + if (!flush->processor_mask) { + local_irq_restore(flags); + return; + } } /* -- cgit v1.2.3