user/sven/linux.git/virt, branch v4.19.94

KVM: arm/arm64: vgic: Don't rely on the wrong pending table

2019-12-13T07:52:45Z

commit ca185b260951d3b55108c0b95e188682d8a507b7 upstream. It's possible that two LPIs locate in the same "byte_offset" but target two different vcpus, where their pending status are indicated by two different pending tables. In such a scenario, using last_byte_offset optimization will lead KVM relying on the wrong pending table entry. Let us use last_ptr instead, which can be treated as a byte index into a pending table and also, can be vcpu specific. Fixes: 280771252c1b ("KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES") Cc: stable@vger.kernel.org Signed-off-by: Zenghui Yu Signed-off-by: Marc Zyngier Acked-by: Eric Auger Link: https://lore.kernel.org/r/20191029071919.177-4-yuzenghui@huawei.com Signed-off-by: Greg Kroah-Hartman

kvm: properly check debugfs dentry before using it

2019-12-05T08:21:14Z

[ Upstream commit 8ed0579c12b2fe56a1fac2f712f58fc26c1dc49b ] debugfs can now report an error code if something went wrong instead of just NULL. So if the return value is to be used as a "real" dentry, it needs to be checked if it is an error before dereferencing it. This is now happening because of ff9fb72bc077 ("debugfs: return error values, not NULL"). syzbot has found a way to trigger multiple debugfs files attempting to be created, which fails, and then the error code gets passed to dentry_path_raw() which obviously does not like it. Reported-by: Eric Biggers Reported-and-tested-by: syzbot+7857962b4d45e602b8ad@syzkaller.appspotmail.com Cc: "Radim Krčmář" Cc: kvm@vger.kernel.org Acked-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

KVM: MMU: Do not treat ZONE_DEVICE pages as being reserved

2019-12-01T08:17:35Z

commit a78986aae9b2988f8493f9f65a587ee433e83bc3 upstream. Explicitly exempt ZONE_DEVICE pages from kvm_is_reserved_pfn() and instead manually handle ZONE_DEVICE on a case-by-case basis. For things like page refcounts, KVM needs to treat ZONE_DEVICE pages like normal pages, e.g. put pages grabbed via gup(). But for flows such as setting A/D bits or shifting refcounts for transparent huge pages, KVM needs to to avoid processing ZONE_DEVICE pages as the flows in question lack the underlying machinery for proper handling of ZONE_DEVICE pages. This fixes a hang reported by Adam Borowski[*] in dev_pagemap_cleanup() when running a KVM guest backed with /dev/dax memory, as KVM straight up doesn't put any references to ZONE_DEVICE pages acquired by gup(). Note, Dan Williams proposed an alternative solution of doing put_page() on ZONE_DEVICE pages immediately after gup() in order to simplify the auditing needed to ensure is_zone_device_page() is called if and only if the backing device is pinned (via gup()). But that approach would break kvm_vcpu_{un}map() as KVM requires the page to be pinned from map() 'til unmap() when accessing guest memory, unlike KVM's secondary MMU, which coordinates with mmu_notifier invalidations to avoid creating stale page references, i.e. doesn't rely on pages being pinned. [*] http://lkml.kernel.org/r/20190919115547.GA17963@angband.pl Reported-by: Adam Borowski Analyzed-by: David Hildenbrand Acked-by: Dan Williams Cc: stable@vger.kernel.org Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini [sean: backport to 4.x; resolve conflict in mmu.c] Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

kvm: arm/arm64: Fix stage2_flush_memslot for 4 level page table

2019-11-24T07:19:31Z

[ Upstream commit d2db7773ba864df6b4e19643dfc54838550d8049 ] So far we have only supported 3 level page table with fixed IPA of 40bits, where PUD is folded. With 4 level page tables, we need to check if the PUD entry is valid or not. Fix stage2_flush_memslot() to do this check, before walking down the table. Acked-by: Christoffer Dall Acked-by: Marc Zyngier Reviewed-by: Eric Auger Signed-off-by: Suzuki K Poulose Signed-off-by: Marc Zyngier Signed-off-by: Sasha Levin

kvm: x86: mmu: Recovery of shattered NX large pages

2019-11-12T18:21:46Z

commit 1aa9b9572b10529c2e64e2b8f44025d86e124308 upstream. The page table pages corresponding to broken down large pages are zapped in FIFO order, so that the large page can potentially be recovered, if it is not longer being used for execution. This removes the performance penalty for walking deeper EPT page tables. By default, one large page will last about one hour once the guest reaches a steady state. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

kvm: Add helper function for creating VM worker threads

2019-11-12T18:21:46Z

commit c57c80467f90e5504c8df9ad3555d2c78800bf94 upstream. Add a function to create a kernel thread associated with a given VM. In particular, it ensures that the worker thread inherits the priority and cgroups of the calling thread. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

kvm: Convert kvm_lock to a mutex

2019-11-12T18:21:40Z

commit 0d9ce162cf46c99628cc5da9510b959c7976735b upstream. It doesn't seem as if there is any particular need for kvm_lock to be a spinlock, so convert the lock to a mutex so that sleepable functions (in particular cond_resched()) can be called while holding it. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

kvm: x86, powerpc: do not allow clearing largepages debugfs entry

2019-11-12T18:21:39Z

commit 833b45de69a6016c4b0cebe6765d526a31a81580 upstream. The largepages debugfs entry is incremented/decremented as shadow pages are created or destroyed. Clearing it will result in an underflow, which is harmless to KVM but ugly (and could be misinterpreted by tools that use debugfs information), so make this particular statistic read-only. Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Cc: kvm-ppc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

KVM: coalesced_mmio: add bounds checking

2019-09-21T05:16:44Z

commit b60fe990c6b07ef6d4df67bc0530c7c90a62623a upstream. The first/last indexes are typically shared with a user app. The app can change the 'last' index that the kernel uses to store the next result. This change sanity checks the index before using it for writing to a potentially arbitrary address. This fixes CVE-2019-14821. Cc: stable@vger.kernel.org Fixes: 5f94c1741bdc ("KVM: Add coalesced MMIO support (common part)") Signed-off-by: Matt Delco Signed-off-by: Jim Mattson Reported-by: syzbot+983c866c3dd6efa3662a@syzkaller.appspotmail.com [Use READ_ONCE. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

kvm: Check irqchip mode before assign irqfd

2019-09-16T06:22:15Z

[ Upstream commit 654f1f13ea56b92bacade8ce2725aea0457f91c0 ] When assigning kvm irqfd we didn't check the irqchip mode but we allow KVM_IRQFD to succeed with all the irqchip modes. However it does not make much sense to create irqfd even without the kernel chips. Let's provide a arch-dependent helper to check whether a specific irqfd is allowed by the arch. At least for x86, it should make sense to check: - when irqchip mode is NONE, all irqfds should be disallowed, and, - when irqchip mode is SPLIT, irqfds that are with resamplefd should be disallowed. For either of the case, previously we'll silently ignore the irq or the irq ack event if the irqchip mode is incorrect. However that can cause misterious guest behaviors and it can be hard to triage. Let's fail KVM_IRQFD even earlier to detect these incorrect configurations. CC: Paolo Bonzini CC: Radim Krčmář CC: Alex Williamson CC: Eduardo Habkost Signed-off-by: Peter Xu Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin