1 files changed, 43 insertions, 14 deletions

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 39e7f6e50919..9cc9e1c1e2db 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -36,9 +36,9 @@ struct hv_flush_pcpu_ex {
 /* Each gva in gva_list encodes up to 4096 pages to flush */
 #define HV_TLB_FLUSH_UNIT (4096 * PAGE_SIZE)
 
-static struct hv_flush_pcpu __percpu *pcpu_flush;
+static struct hv_flush_pcpu __percpu **pcpu_flush;
 
-static struct hv_flush_pcpu_ex __percpu *pcpu_flush_ex;
+static struct hv_flush_pcpu_ex __percpu **pcpu_flush_ex;
 
 /*
  * Fills in gva_list starting from offset. Returns the number of items added.
@@ -76,6 +76,18 @@ static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
 {
         int cpu, vcpu, vcpu_bank, vcpu_offset, nr_bank = 1;
 
+        /* valid_bank_mask can represent up to 64 banks */
+        if (hv_max_vp_index / 64 >= 64)
+                return 0;
+
+        /*
+         * Clear all banks up to the maximum possible bank as hv_flush_pcpu_ex
+         * structs are not cleared between calls, we risk flushing unneeded
+         * vCPUs otherwise.
+         */
+        for (vcpu_bank = 0; vcpu_bank <= hv_max_vp_index / 64; vcpu_bank++)
+                flush->hv_vp_set.bank_contents[vcpu_bank] = 0;
+
         /*
          * Some banks may end up being empty but this is acceptable.
          */
@@ -83,11 +95,6 @@ static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
                 vcpu = hv_cpu_number_to_vp_number(cpu);
                 vcpu_bank = vcpu / 64;
                 vcpu_offset = vcpu % 64;
-
-                /* valid_bank_mask can represent up to 64 banks */
-                if (vcpu_bank >= 64)
-                        return 0;
-
                 __set_bit(vcpu_offset, (unsigned long *)
                           &flush->hv_vp_set.bank_contents[vcpu_bank]);
                 if (vcpu_bank >= nr_bank)
@@ -102,6 +109,7 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
                                     const struct flush_tlb_info *info)
 {
         int cpu, vcpu, gva_n, max_gvas;
+        struct hv_flush_pcpu **flush_pcpu;
         struct hv_flush_pcpu *flush;
         u64 status = U64_MAX;
         unsigned long flags;
@@ -116,7 +124,17 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
 
         local_irq_save(flags);
 
-        flush = this_cpu_ptr(pcpu_flush);
+        flush_pcpu = this_cpu_ptr(pcpu_flush);
+
+        if (unlikely(!*flush_pcpu))
+                *flush_pcpu = page_address(alloc_page(GFP_ATOMIC));
+
+        flush = *flush_pcpu;
+
+        if (unlikely(!flush)) {
+                local_irq_restore(flags);
+                goto do_native;
+        }
 
         if (info->mm) {
                 flush->address_space = virt_to_phys(info->mm->pgd);
@@ -173,6 +191,7 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
                                        const struct flush_tlb_info *info)
 {
         int nr_bank = 0, max_gvas, gva_n;
+        struct hv_flush_pcpu_ex **flush_pcpu;
         struct hv_flush_pcpu_ex *flush;
         u64 status = U64_MAX;
         unsigned long flags;
@@ -187,7 +206,17 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 
         local_irq_save(flags);
 
-        flush = this_cpu_ptr(pcpu_flush_ex);
+        flush_pcpu = this_cpu_ptr(pcpu_flush_ex);
+
+        if (unlikely(!*flush_pcpu))
+                *flush_pcpu = page_address(alloc_page(GFP_ATOMIC));
+
+        flush = *flush_pcpu;
+
+        if (unlikely(!flush)) {
+                local_irq_restore(flags);
+                goto do_native;
+        }
 
         if (info->mm) {
                 flush->address_space = virt_to_phys(info->mm->pgd);
@@ -222,18 +251,18 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
-                        0, nr_bank + 2, flush, NULL);
+                        0, nr_bank, flush, NULL);
         } else if (info->end &&
                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
-                        0, nr_bank + 2, flush, NULL);
+                        0, nr_bank, flush, NULL);
         } else {
                 gva_n = fill_gva_list(flush->gva_list, nr_bank,
                                       info->start, info->end);
                 status = hv_do_rep_hypercall(
                         HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
-                        gva_n, nr_bank + 2, flush, NULL);
+                        gva_n, nr_bank, flush, NULL);
         }
 
         local_irq_restore(flags);
@@ -266,7 +295,7 @@ void hyper_alloc_mmu(void)
                 return;
 
         if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
-                pcpu_flush = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
+                pcpu_flush = alloc_percpu(struct hv_flush_pcpu *);
         else
-                pcpu_flush_ex = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
+                pcpu_flush_ex = alloc_percpu(struct hv_flush_pcpu_ex *);
 }