| From 2d651ed23384c2a440f34ffab0b2a23ccb1ee07b Mon Sep 17 00:00:00 2001 |
| From: Marc Zyngier <marc.zyngier@arm.com> |
| Date: Tue, 19 Mar 2019 12:56:23 +0000 |
| Subject: KVM: arm/arm64: vgic-its: Take the srcu lock when parsing the |
| memslots |
| |
| [ Upstream commit 7494cec6cb3ba7385a6a223b81906384f15aae34 ] |
| |
| Calling kvm_is_visible_gfn() implies that we're parsing the memslots, |
| and doing this without the srcu lock is frown upon: |
| |
| [12704.164532] ============================= |
| [12704.164544] WARNING: suspicious RCU usage |
| [12704.164560] 5.1.0-rc1-00008-g600025238f51-dirty #16 Tainted: G W |
| [12704.164573] ----------------------------- |
| [12704.164589] ./include/linux/kvm_host.h:605 suspicious rcu_dereference_check() usage! |
| [12704.164602] other info that might help us debug this: |
| [12704.164616] rcu_scheduler_active = 2, debug_locks = 1 |
| [12704.164631] 6 locks held by qemu-system-aar/13968: |
| [12704.164644] #0: 000000007ebdae4f (&kvm->lock){+.+.}, at: vgic_its_set_attr+0x244/0x3a0 |
| [12704.164691] #1: 000000007d751022 (&its->its_lock){+.+.}, at: vgic_its_set_attr+0x250/0x3a0 |
| [12704.164726] #2: 00000000219d2706 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 |
| [12704.164761] #3: 00000000a760aecd (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 |
| [12704.164794] #4: 000000000ef8e31d (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 |
| [12704.164827] #5: 000000007a872093 (&vcpu->mutex){+.+.}, at: lock_all_vcpus+0x64/0xd0 |
| [12704.164861] stack backtrace: |
| [12704.164878] CPU: 2 PID: 13968 Comm: qemu-system-aar Tainted: G W 5.1.0-rc1-00008-g600025238f51-dirty #16 |
| [12704.164887] Hardware name: rockchip evb_rk3399/evb_rk3399, BIOS 2019.04-rc3-00124-g2feec69fb1 03/15/2019 |
| [12704.164896] Call trace: |
| [12704.164910] dump_backtrace+0x0/0x138 |
| [12704.164920] show_stack+0x24/0x30 |
| [12704.164934] dump_stack+0xbc/0x104 |
| [12704.164946] lockdep_rcu_suspicious+0xcc/0x110 |
| [12704.164958] gfn_to_memslot+0x174/0x190 |
| [12704.164969] kvm_is_visible_gfn+0x28/0x70 |
| [12704.164980] vgic_its_check_id.isra.0+0xec/0x1e8 |
| [12704.164991] vgic_its_save_tables_v0+0x1ac/0x330 |
| [12704.165001] vgic_its_set_attr+0x298/0x3a0 |
| [12704.165012] kvm_device_ioctl_attr+0x9c/0xd8 |
| [12704.165022] kvm_device_ioctl+0x8c/0xf8 |
| [12704.165035] do_vfs_ioctl+0xc8/0x960 |
| [12704.165045] ksys_ioctl+0x8c/0xa0 |
| [12704.165055] __arm64_sys_ioctl+0x28/0x38 |
| [12704.165067] el0_svc_common+0xd8/0x138 |
| [12704.165078] el0_svc_handler+0x38/0x78 |
| [12704.165089] el0_svc+0x8/0xc |
| |
| Make sure the lock is taken when doing this. |
| |
| Fixes: bf308242ab98 ("KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock") |
| Reviewed-by: Eric Auger <eric.auger@redhat.com> |
| Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> |
| Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org> |
| --- |
| virt/kvm/arm/vgic/vgic-its.c | 13 ++++++++++--- |
| 1 file changed, 10 insertions(+), 3 deletions(-) |
| |
| diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c |
| index d72b8481f250..dc06f5e40041 100644 |
| --- a/virt/kvm/arm/vgic/vgic-its.c |
| +++ b/virt/kvm/arm/vgic/vgic-its.c |
| @@ -704,8 +704,9 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, |
| int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K; |
| u64 indirect_ptr, type = GITS_BASER_TYPE(baser); |
| int esz = GITS_BASER_ENTRY_SIZE(baser); |
| - int index; |
| + int index, idx; |
| gfn_t gfn; |
| + bool ret; |
| |
| switch (type) { |
| case GITS_BASER_TYPE_DEVICE: |
| @@ -732,7 +733,8 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, |
| |
| if (eaddr) |
| *eaddr = addr; |
| - return kvm_is_visible_gfn(its->dev->kvm, gfn); |
| + |
| + goto out; |
| } |
| |
| /* calculate and check the index into the 1st level */ |
| @@ -766,7 +768,12 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id, |
| |
| if (eaddr) |
| *eaddr = indirect_ptr; |
| - return kvm_is_visible_gfn(its->dev->kvm, gfn); |
| + |
| +out: |
| + idx = srcu_read_lock(&its->dev->kvm->srcu); |
| + ret = kvm_is_visible_gfn(its->dev->kvm, gfn); |
| + srcu_read_unlock(&its->dev->kvm->srcu, idx); |
| + return ret; |
| } |
| |
| static int vgic_its_alloc_collection(struct vgic_its *its, |
| -- |
| 2.19.1 |
| |