From 597cb7968cb6243e915ba9599195656be14773e5 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Tue, 4 Jan 2022 22:41:03 -0800 Subject: KVM: SEV: Mark nested locking of kvm->lock Both source and dest vms' kvm->locks are held in sev_lock_two_vms. Mark one with a different subtype to avoid false positives from lockdep. Fixes: c9d61dcb0bc26 (KVM: SEV: accept signals in sev_lock_two_vms) Reported-by: Yiru Xu Tested-by: Jinrong Liang Signed-off-by: Wanpeng Li Message-Id: <1641364863-26331-1-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 7656a2c5662a..be2883141220 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1565,7 +1565,7 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) r = -EINTR; if (mutex_lock_killable(&dst_kvm->lock)) goto release_src; - if (mutex_lock_killable(&src_kvm->lock)) + if (mutex_lock_killable_nested(&src_kvm->lock, SINGLE_DEPTH_NESTING)) goto unlock_dst; return 0; -- cgit From fffb5323780786c81ba005f8b8603d4a558aad28 Mon Sep 17 00:00:00 2001 From: Nikunj A Dadhania Date: Wed, 5 Jan 2022 09:33:37 +0530 Subject: KVM: x86: Check for rmaps allocation With TDP MMU being the default now, access to mmu_rmaps_stat debugfs file causes following oops: BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 7 PID: 3185 Comm: cat Not tainted 5.16.0-rc4+ #204 RIP: 0010:pte_list_count+0x6/0x40 Call Trace: ? kvm_mmu_rmaps_stat_show+0x15e/0x320 seq_read_iter+0x126/0x4b0 ? aa_file_perm+0x124/0x490 seq_read+0xf5/0x140 full_proxy_read+0x5c/0x80 vfs_read+0x9f/0x1a0 ksys_read+0x67/0xe0 __x64_sys_read+0x19/0x20 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fca6fc13912 Return early when rmaps are not present. Reported-by: Vasant Hegde Tested-by: Vasant Hegde Signed-off-by: Nikunj A Dadhania Reviewed-by: Peter Xu Reviewed-by: Sean Christopherson Message-Id: <20220105040337.4234-1-nikunj@amd.com> Cc: stable@vger.kernel.org Fixes: 3bcd0662d66f ("KVM: X86: Introduce mmu_rmaps_stat per-vm debugfs file") Signed-off-by: Paolo Bonzini --- arch/x86/kvm/debugfs.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index 54a83a744538..f33c804a922a 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -95,6 +95,9 @@ static int kvm_mmu_rmaps_stat_show(struct seq_file *m, void *v) unsigned int *log[KVM_NR_PAGE_SIZES], *cur; int i, j, k, l, ret; + if (!kvm_memslots_have_rmaps(kvm)) + return 0; + ret = -ENOMEM; memset(log, 0, sizeof(log)); for (i = 0; i < KVM_NR_PAGE_SIZES; i++) { -- cgit From 5f02ef741a785678930f3ff0a8b6b2b0ef1bb402 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 18 Jan 2022 04:34:43 -0500 Subject: KVM: VMX: switch blocked_vcpu_on_cpu_lock to raw spinlock blocked_vcpu_on_cpu_lock is taken from hard interrupt context (pi_wakeup_handler), therefore it cannot sleep. Switch it to a raw spinlock. Fixes: [41297.066254] BUG: scheduling while atomic: CPU 0/KVM/635218/0x00010001 [41297.066323] Preemption disabled at: [41297.066324] [] irq_enter_rcu+0xf/0x60 [41297.066339] Call Trace: [41297.066342] [41297.066346] dump_stack_lvl+0x34/0x44 [41297.066353] ? irq_enter_rcu+0xf/0x60 [41297.066356] __schedule_bug.cold+0x7d/0x8b [41297.066361] __schedule+0x439/0x5b0 [41297.066365] ? task_blocks_on_rt_mutex.constprop.0.isra.0+0x1b0/0x440 [41297.066369] schedule_rtlock+0x1e/0x40 [41297.066371] rtlock_slowlock_locked+0xf1/0x260 [41297.066374] rt_spin_lock+0x3b/0x60 [41297.066378] pi_wakeup_handler+0x31/0x90 [kvm_intel] [41297.066388] sysvec_kvm_posted_intr_wakeup_ipi+0x9d/0xd0 [41297.066392] [41297.066392] asm_sysvec_kvm_posted_intr_wakeup_ipi+0x12/0x20 ... Signed-off-by: Marcelo Tosatti Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/posted_intr.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 1c94783b5a54..21ea58d25771 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -15,7 +15,7 @@ * can find which vCPU should be waken up. */ static DEFINE_PER_CPU(struct list_head, blocked_vcpu_on_cpu); -static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock); +static DEFINE_PER_CPU(raw_spinlock_t, blocked_vcpu_on_cpu_lock); static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu) { @@ -121,9 +121,9 @@ static void __pi_post_block(struct kvm_vcpu *vcpu) new.control) != old.control); if (!WARN_ON_ONCE(vcpu->pre_pcpu == -1)) { - spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); + raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); list_del(&vcpu->blocked_vcpu_list); - spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); + raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); vcpu->pre_pcpu = -1; } } @@ -154,11 +154,11 @@ int pi_pre_block(struct kvm_vcpu *vcpu) local_irq_disable(); if (!WARN_ON_ONCE(vcpu->pre_pcpu != -1)) { vcpu->pre_pcpu = vcpu->cpu; - spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); + raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); list_add_tail(&vcpu->blocked_vcpu_list, &per_cpu(blocked_vcpu_on_cpu, vcpu->pre_pcpu)); - spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); + raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, vcpu->pre_pcpu)); } do { @@ -215,7 +215,7 @@ void pi_wakeup_handler(void) struct kvm_vcpu *vcpu; int cpu = smp_processor_id(); - spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + raw_spin_lock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); list_for_each_entry(vcpu, &per_cpu(blocked_vcpu_on_cpu, cpu), blocked_vcpu_list) { struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); @@ -223,13 +223,13 @@ void pi_wakeup_handler(void) if (pi_test_on(pi_desc) == 1) kvm_vcpu_kick(vcpu); } - spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + raw_spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); } void __init pi_init_cpu(int cpu) { INIT_LIST_HEAD(&per_cpu(blocked_vcpu_on_cpu, cpu)); - spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); + raw_spin_lock_init(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); } bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu) -- cgit