1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * KVM L1 hypervisor optimizations on Hyper-V. 4 */ 5 6 #include <linux/kvm_host.h> 7 #include <asm/mshyperv.h> 8 9 #include "hyperv.h" 10 #include "kvm_onhyperv.h" 11 12 static int kvm_fill_hv_flush_list_func(struct hv_guest_mapping_flush_list *flush, 13 void *data) 14 { 15 struct kvm_tlb_range *range = data; 16 17 return hyperv_fill_flush_guest_mapping_list(flush, range->start_gfn, 18 range->pages); 19 } 20 21 static inline int hv_remote_flush_root_tdp(hpa_t root_tdp, 22 struct kvm_tlb_range *range) 23 { 24 if (range) 25 return hyperv_flush_guest_mapping_range(root_tdp, 26 kvm_fill_hv_flush_list_func, (void *)range); 27 else 28 return hyperv_flush_guest_mapping(root_tdp); 29 } 30 31 int hv_remote_flush_tlb_with_range(struct kvm *kvm, 32 struct kvm_tlb_range *range) 33 { 34 struct kvm_arch *kvm_arch = &kvm->arch; 35 struct kvm_vcpu *vcpu; 36 int ret = 0, nr_unique_valid_roots; 37 unsigned long i; 38 hpa_t root; 39 40 spin_lock(&kvm_arch->hv_root_tdp_lock); 41 42 if (!VALID_PAGE(kvm_arch->hv_root_tdp)) { 43 nr_unique_valid_roots = 0; 44 45 /* 46 * Flush all valid roots, and see if all vCPUs have converged 47 * on a common root, in which case future flushes can skip the 48 * loop and flush the common root. 49 */ 50 kvm_for_each_vcpu(i, vcpu, kvm) { 51 root = vcpu->arch.hv_root_tdp; 52 if (!VALID_PAGE(root) || root == kvm_arch->hv_root_tdp) 53 continue; 54 55 /* 56 * Set the tracked root to the first valid root. Keep 57 * this root for the entirety of the loop even if more 58 * roots are encountered as a low effort optimization 59 * to avoid flushing the same (first) root again. 60 */ 61 if (++nr_unique_valid_roots == 1) 62 kvm_arch->hv_root_tdp = root; 63 64 if (!ret) 65 ret = hv_remote_flush_root_tdp(root, range); 66 67 /* 68 * Stop processing roots if a failure occurred and 69 * multiple valid roots have already been detected. 70 */ 71 if (ret && nr_unique_valid_roots > 1) 72 break; 73 } 74 75 /* 76 * The optimized flush of a single root can't be used if there 77 * are multiple valid roots (obviously). 78 */ 79 if (nr_unique_valid_roots > 1) 80 kvm_arch->hv_root_tdp = INVALID_PAGE; 81 } else { 82 ret = hv_remote_flush_root_tdp(kvm_arch->hv_root_tdp, range); 83 } 84 85 spin_unlock(&kvm_arch->hv_root_tdp_lock); 86 return ret; 87 } 88 EXPORT_SYMBOL_GPL(hv_remote_flush_tlb_with_range); 89 90 int hv_remote_flush_tlb(struct kvm *kvm) 91 { 92 return hv_remote_flush_tlb_with_range(kvm, NULL); 93 } 94 EXPORT_SYMBOL_GPL(hv_remote_flush_tlb); 95