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, i, nr_unique_valid_roots; 37 hpa_t root; 38 39 spin_lock(&kvm_arch->hv_root_tdp_lock); 40 41 if (!VALID_PAGE(kvm_arch->hv_root_tdp)) { 42 nr_unique_valid_roots = 0; 43 44 /* 45 * Flush all valid roots, and see if all vCPUs have converged 46 * on a common root, in which case future flushes can skip the 47 * loop and flush the common root. 48 */ 49 kvm_for_each_vcpu(i, vcpu, kvm) { 50 root = vcpu->arch.hv_root_tdp; 51 if (!VALID_PAGE(root) || root == kvm_arch->hv_root_tdp) 52 continue; 53 54 /* 55 * Set the tracked root to the first valid root. Keep 56 * this root for the entirety of the loop even if more 57 * roots are encountered as a low effort optimization 58 * to avoid flushing the same (first) root again. 59 */ 60 if (++nr_unique_valid_roots == 1) 61 kvm_arch->hv_root_tdp = root; 62 63 if (!ret) 64 ret = hv_remote_flush_root_tdp(root, range); 65 66 /* 67 * Stop processing roots if a failure occurred and 68 * multiple valid roots have already been detected. 69 */ 70 if (ret && nr_unique_valid_roots > 1) 71 break; 72 } 73 74 /* 75 * The optimized flush of a single root can't be used if there 76 * are multiple valid roots (obviously). 77 */ 78 if (nr_unique_valid_roots > 1) 79 kvm_arch->hv_root_tdp = INVALID_PAGE; 80 } else { 81 ret = hv_remote_flush_root_tdp(kvm_arch->hv_root_tdp, range); 82 } 83 84 spin_unlock(&kvm_arch->hv_root_tdp_lock); 85 return ret; 86 } 87 EXPORT_SYMBOL_GPL(hv_remote_flush_tlb_with_range); 88 89 int hv_remote_flush_tlb(struct kvm *kvm) 90 { 91 return hv_remote_flush_tlb_with_range(kvm, NULL); 92 } 93 EXPORT_SYMBOL_GPL(hv_remote_flush_tlb); 94