kernel.git/virt/kvm/kvm_main.c, branch linux-3.2.y

KVM: nVMX: Fix memory corruption when using VMCS shadowing

2016-11-20T01:01:26Z

commit 2f1fe81123f59271bddda673b60116bde9660385 upstream. When freeing the nested resources of a vcpu, there is an assumption that the vcpu's vmcs01 is the current VMCS on the CPU that executes nested_release_vmcs12(). If this assumption is violated, the vcpu's vmcs01 may be made active on multiple CPUs at the same time, in violation of Intel's specification. Moreover, since the vcpu's vmcs01 is not VMCLEARed on every CPU on which it is active, it can linger in a CPU's VMCS cache after it has been freed and potentially repurposed. Subsequent eviction from the CPU's VMCS cache on a capacity miss can result in memory corruption. It is not sufficient for vmx_free_vcpu() to call vmx_load_vmcs01(). If the vcpu in question was last loaded on a different CPU, it must be migrated to the current CPU before calling vmx_load_vmcs01(). Signed-off-by: Jim Mattson Signed-off-by: Paolo Bonzini [bwh: Backported to 3.2: vcpu_load() returns void] Signed-off-by: Ben Hutchings

kvm: don't take vcpu mutex for obviously invalid vcpu ioctls

2014-12-14T16:23:44Z

commit 2ea75be3219571d0ec009ce20d9971e54af96e09 upstream. vcpu ioctls can hang the calling thread if issued while a vcpu is running. However, invalid ioctls can happen when userspace tries to probe the kind of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case, we know the ioctl is going to be rejected as invalid anyway and we can fail before trying to take the vcpu mutex. This patch does not change functionality, it just makes invalid ioctls fail faster. Signed-off-by: David Matlack Signed-off-by: Paolo Bonzini [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

KVM: Fix iommu map/unmap to handle memory slot moves

2014-01-03T04:33:35Z

commit e40f193f5bb022e927a57a4f5d5194e4f12ddb74 upstream. The iommu integration into memory slots expects memory slots to be added or removed and doesn't handle the move case. We can unmap slots from the iommu after we mark them invalid and map them before installing the final memslot array. Also re-order the kmemdup vs map so we don't leave iommu mappings if we get ENOMEM. Reviewed-by: Gleb Natapov Signed-off-by: Alex Williamson Signed-off-by: Marcelo Tosatti [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

KVM: perform an invalid memslot step for gpa base change

2014-01-03T04:33:35Z

commit 12d6e7538e2d418c08f082b1b44ffa5fb7270ed8 upstream. PPC must flush all translations before the new memory slot is visible. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

KVM: Improve create VCPU parameter (CVE-2013-4587)

2014-01-03T04:33:31Z

commit 338c7dbadd2671189cec7faf64c84d01071b3f96 upstream. In multiple functions the vcpu_id is used as an offset into a bitfield. Ag malicious user could specify a vcpu_id greater than 255 in order to set or clear bits in kernel memory. This could be used to elevate priveges in the kernel. This patch verifies that the vcpu_id provided is less than 255. The api documentation already specifies that the vcpu_id must be less than max_vcpus, but this is currently not checked. Reported-by: Andrew Honig Signed-off-by: Andrew Honig Signed-off-by: Paolo Bonzini Signed-off-by: Ben Hutchings

KVM: Allow cross page reads and writes from cached translations.

2013-04-25T19:25:50Z

commit 8f964525a121f2ff2df948dac908dcc65be21b5b upstream. This patch adds support for kvm_gfn_to_hva_cache_init functions for reads and writes that will cross a page. If the range falls within the same memslot, then this will be a fast operation. If the range is split between two memslots, then the slower kvm_read_guest and kvm_write_guest are used. Tested: Test against kvm_clock unit tests. Signed-off-by: Andrew Honig Signed-off-by: Gleb Natapov [bwh: Backported to 3.2: - Drop change in lapic.c - Keep using __gfn_to_memslot() in kvm_gfn_to_hva_cache_init()] Signed-off-by: Ben Hutchings

KVM: Ensure all vcpus are consistent with in-kernel irqchip settings

2012-05-30T23:43:10Z

(cherry picked from commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e) If some vcpus are created before KVM_CREATE_IRQCHIP, then irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to potential NULL pointer dereferences. Fix by: - ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called - ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP This is somewhat long winded because vcpu->arch.apic is created without kvm->lock held. Based on earlier patch by Michael Ellerman. Signed-off-by: Michael Ellerman Signed-off-by: Avi Kivity Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

KVM: mmu_notifier: Flush TLBs before releasing mmu_lock

2012-05-30T23:43:09Z

(cherry picked from commit 565f3be2174611f364405bbea2d86e153c2e7e78 Other threads may process the same page in that small window and skip TLB flush and then return before these functions do flush. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity Signed-off-by: Ben Hutchings

KVM: unmap pages from the iommu when slots are removed

2012-05-11T12:14:07Z

commit 32f6daad4651a748a58a3ab6da0611862175722f upstream. We've been adding new mappings, but not destroying old mappings. This can lead to a page leak as pages are pinned using get_user_pages, but only unpinned with put_page if they still exist in the memslots list on vm shutdown. A memslot that is destroyed while an iommu domain is enabled for the guest will therefore result in an elevated page reference count that is never cleared. Additionally, without this fix, the iommu is only programmed with the first translation for a gpa. This can result in peer-to-peer errors if a mapping is destroyed and replaced by a new mapping at the same gpa as the iommu will still be pointing to the original, pinned memory address. Signed-off-by: Alex Williamson Signed-off-by: Marcelo Tosatti Signed-off-by: Jonathan Nieder Signed-off-by: Ben Hutchings

KVM: Intelligent device lookup on I/O bus

2011-09-25T16:17:59Z

Currently the method of dealing with an IO operation on a bus (PIO/MMIO) is to call the read or write callback for each device registered on the bus until we find a device which handles it. Since the number of devices on a bus can be significant due to ioeventfds and coalesced MMIO zones, this leads to a lot of overhead on each IO operation. Instead of registering devices, we now register ranges which points to a device. Lookup is done using an efficient bsearch instead of a linear search. Performance test was conducted by comparing exit count per second with 200 ioeventfds created on one byte and the guest is trying to access a different byte continuously (triggering usermode exits). Before the patch the guest has achieved 259k exits per second, after the patch the guest does 274k exits per second. Cc: Avi Kivity Cc: Marcelo Tosatti Signed-off-by: Sasha Levin Signed-off-by: Avi Kivity