From 72dc67a69690288538142df73a7e3ac66fea68dc Mon Sep 17 00:00:00 2001 From: Izik Eidus Date: Sun, 10 Feb 2008 18:04:15 +0200 Subject: KVM: remove the usage of the mmap_sem for the protection of the memory slots. This patch replaces the mmap_sem lock for the memory slots with a new kvm private lock, it is needed beacuse untill now there were cases where kvm accesses user memory while holding the mmap semaphore. Signed-off-by: Izik Eidus Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 65 +++++++++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 28 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 338764fa5391..6b01552bd1f1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -184,7 +184,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) int ret; u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)]; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte, offset * sizeof(u64), sizeof(pdpte)); if (ret < 0) { @@ -201,7 +201,7 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs)); out: - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); return ret; } @@ -215,13 +215,13 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu) if (is_long_mode(vcpu) || !is_pae(vcpu)) return false; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte)); if (r < 0) goto out; changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0; out: - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); return changed; } @@ -359,7 +359,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) */ } - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); /* * Does the new cr3 value map to physical memory? (Note, we * catch an invalid cr3 even in real-mode, because it would @@ -375,7 +375,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) vcpu->arch.cr3 = cr3; vcpu->arch.mmu.new_cr3(vcpu); } - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); } EXPORT_SYMBOL_GPL(set_cr3); @@ -1232,12 +1232,12 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES) return -EINVAL; - down_write(¤t->mm->mmap_sem); + down_write(&kvm->slots_lock); kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages); kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages; - up_write(¤t->mm->mmap_sem); + up_write(&kvm->slots_lock); return 0; } @@ -1286,7 +1286,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm, < alias->target_phys_addr) goto out; - down_write(¤t->mm->mmap_sem); + down_write(&kvm->slots_lock); p = &kvm->arch.aliases[alias->slot]; p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT; @@ -1300,7 +1300,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm, kvm_mmu_zap_all(kvm); - up_write(¤t->mm->mmap_sem); + up_write(&kvm->slots_lock); return 0; @@ -1376,7 +1376,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot; int is_dirty = 0; - down_write(¤t->mm->mmap_sem); + down_write(&kvm->slots_lock); r = kvm_get_dirty_log(kvm, log, &is_dirty); if (r) @@ -1392,7 +1392,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, } r = 0; out: - up_write(¤t->mm->mmap_sem); + up_write(&kvm->slots_lock); return r; } @@ -1570,7 +1570,7 @@ int emulator_read_std(unsigned long addr, void *data = val; int r = X86EMUL_CONTINUE; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); while (bytes) { gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr); unsigned offset = addr & (PAGE_SIZE-1); @@ -1592,7 +1592,7 @@ int emulator_read_std(unsigned long addr, addr += tocopy; } out: - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); return r; } EXPORT_SYMBOL_GPL(emulator_read_std); @@ -1611,9 +1611,9 @@ static int emulator_read_emulated(unsigned long addr, return X86EMUL_CONTINUE; } - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr); - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); /* For APIC access vmexit */ if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE) @@ -1651,14 +1651,14 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, { int ret; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes); if (ret < 0) { - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); return 0; } kvm_mmu_pte_write(vcpu, gpa, val, bytes); - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); return 1; } @@ -1670,9 +1670,9 @@ static int emulator_write_emulated_onepage(unsigned long addr, struct kvm_io_device *mmio_dev; gpa_t gpa; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr); - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); if (gpa == UNMAPPED_GVA) { kvm_inject_page_fault(vcpu, addr, 2); @@ -1749,7 +1749,7 @@ static int emulator_cmpxchg_emulated(unsigned long addr, char *kaddr; u64 val; - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr); if (gpa == UNMAPPED_GVA || @@ -1760,13 +1760,17 @@ static int emulator_cmpxchg_emulated(unsigned long addr, goto emul_write; val = *(u64 *)new; + + down_read(¤t->mm->mmap_sem); page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); + up_read(¤t->mm->mmap_sem); + kaddr = kmap_atomic(page, KM_USER0); set_64bit((u64 *)(kaddr + offset_in_page(gpa)), val); kunmap_atomic(kaddr, KM_USER0); kvm_release_page_dirty(page); emul_write: - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); } #endif @@ -2159,10 +2163,10 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, kvm_x86_ops->skip_emulated_instruction(vcpu); for (i = 0; i < nr_pages; ++i) { - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); page = gva_to_page(vcpu, address + i * PAGE_SIZE); vcpu->arch.pio.guest_pages[i] = page; - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); if (!page) { kvm_inject_gp(vcpu, 0); free_pio_guest_pages(vcpu); @@ -2485,8 +2489,9 @@ static void vapic_enter(struct kvm_vcpu *vcpu) down_read(¤t->mm->mmap_sem); page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT); - vcpu->arch.apic->vapic_page = page; up_read(¤t->mm->mmap_sem); + + vcpu->arch.apic->vapic_page = page; } static void vapic_exit(struct kvm_vcpu *vcpu) @@ -2959,9 +2964,9 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu, gpa_t gpa; vcpu_load(vcpu); - down_read(¤t->mm->mmap_sem); + down_read(&vcpu->kvm->slots_lock); gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, vaddr); - up_read(¤t->mm->mmap_sem); + up_read(&vcpu->kvm->slots_lock); tr->physical_address = gpa; tr->valid = gpa != UNMAPPED_GVA; tr->writeable = 1; @@ -3234,11 +3239,13 @@ int kvm_arch_set_memory_region(struct kvm *kvm, */ if (!user_alloc) { if (npages && !old.rmap) { + down_write(¤t->mm->mmap_sem); memslot->userspace_addr = do_mmap(NULL, 0, npages * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, 0); + up_write(¤t->mm->mmap_sem); if (IS_ERR((void *)memslot->userspace_addr)) return PTR_ERR((void *)memslot->userspace_addr); @@ -3246,8 +3253,10 @@ int kvm_arch_set_memory_region(struct kvm *kvm, if (!old.user_alloc && old.rmap) { int ret; + down_write(¤t->mm->mmap_sem); ret = do_munmap(current->mm, old.userspace_addr, old.npages * PAGE_SIZE); + up_write(¤t->mm->mmap_sem); if (ret < 0) printk(KERN_WARNING "kvm_vm_ioctl_set_memory_region: " -- cgit v1.2.3