kernel.git/arch/arm/kvm, branch linux-4.8.y

kvm-arm: Unmap shadow pagetables properly

2016-09-09T10:40:30Z

On arm/arm64, we depend on the kvm_unmap_hva* callbacks (via mmu_notifiers::invalidate_*) to unmap the stage2 pagetables when the userspace buffer gets unmapped. However, when the Hypervisor process exits without explicit unmap of the guest buffers, the only notifier we get is kvm_arch_flush_shadow_all() (via mmu_notifier::release ) which does nothing on arm. Later this causes us to access pages that were already released [via exit_mmap() -> unmap_vmas()] when we actually get to unmap the stage2 pagetable [via kvm_arch_destroy_vm() -> kvm_free_stage2_pgd()]. This triggers crashes with CONFIG_DEBUG_PAGEALLOC, which unmaps any free'd pages from the linear map. [ 757.644120] Unable to handle kernel paging request at virtual address ffff800661e00000 [ 757.652046] pgd = ffff20000b1a2000 [ 757.655471] [ffff800661e00000] *pgd=00000047fffe3003, *pud=00000047fcd8c003, *pmd=00000047fcc7c003, *pte=00e8004661e00712 [ 757.666492] Internal error: Oops: 96000147 [#3] PREEMPT SMP [ 757.672041] Modules linked in: [ 757.675100] CPU: 7 PID: 3630 Comm: qemu-system-aar Tainted: G D 4.8.0-rc1 #3 [ 757.683240] Hardware name: AppliedMicro X-Gene Mustang Board/X-Gene Mustang Board, BIOS 3.06.15 Aug 19 2016 [ 757.692938] task: ffff80069cdd3580 task.stack: ffff8006adb7c000 [ 757.698840] PC is at __flush_dcache_area+0x1c/0x40 [ 757.703613] LR is at kvm_flush_dcache_pmd+0x60/0x70 [ 757.708469] pc : [] lr : [] pstate: 20000145 ... [ 758.357249] [] __flush_dcache_area+0x1c/0x40 [ 758.363059] [] unmap_stage2_range+0x458/0x5f0 [ 758.368954] [] kvm_free_stage2_pgd+0x34/0x60 [ 758.374761] [] kvm_arch_destroy_vm+0x20/0x68 [ 758.380570] [] kvm_put_kvm+0x210/0x358 [ 758.385860] [] kvm_vm_release+0x2c/0x40 [ 758.391239] [] __fput+0x114/0x2e8 [ 758.396096] [] ____fput+0xc/0x18 [ 758.400869] [] task_work_run+0x108/0x138 [ 758.406332] [] do_exit+0x48c/0x10e8 [ 758.411363] [] do_group_exit+0x6c/0x130 [ 758.416739] [] get_signal+0x284/0xa18 [ 758.421943] [] do_signal+0x158/0x860 [ 758.427060] [] do_notify_resume+0x6c/0x88 [ 758.432608] [] work_pending+0x10/0x14 [ 758.437812] Code: 9ac32042 8b010001 d1000443 8a230000 (d50b7e20) This patch fixes the issue by moving the kvm_free_stage2_pgd() to kvm_arch_flush_shadow_all(). Cc: # 3.9+ Tested-by: Itaru Kitayama Reported-by: Itaru Kitayama Reported-by: James Morse Cc: Marc Zyngier Cc: Catalin Marinas Cc: Christoffer Dall Signed-off-by: Suzuki K Poulose Signed-off-by: Christoffer Dall

arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed

2016-09-06T11:09:31Z

We're trying hard to detect when the HYP idmap overlaps with the HYP va, as it makes the teardown of a cpu dangerous. But there is one case where an overlap is completely safe, which is when the whole of the kernel is idmap'ed, which is likely to happen on 32bit when RAM is at 0x8000000 and we're using a 2G/2G VA split. In that case, we can proceed safely. Reported-by: Christoffer Dall Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall

Merge tag 'kvm-arm-for-v4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2016-08-18T10:19:19Z

KVM/ARM Fixes for v4.8-rc3 This tag contains the following fixes on top of v4.8-rc1: - ITS init issues - ITS error handling issues - ITS IRQ leakage fix - Plug a couple of ITS race conditions - An erratum workaround for timers - Some removal of misleading use of errors and comments - A fix for GICv3 on 32-bit guests

KVM: arm/arm64: Change misleading use of is_error_pfn

2016-08-17T09:38:03Z

When converting a gfn to a pfn, we call gfn_to_pfn_prot, which returns various kinds of error values. It turns out that is_error_pfn() only returns true when the gfn was found in a memory slot and could somehow not be used, but it does not return true if the gfn does not belong to any memory slot. Change use to is_error_noslot_pfn() which covers both cases. Note: Since we already check for kvm_is_error_hva(hva) explicitly in the caller of this function while holding the kvm->srcu lock protecting the memory slots, this should never be a problem, but nevertheless this change is warranted as it shows the intention of the code. Reported-by: James Hogan Signed-off-by: Christoffer Dall

KVM: Protect device ops->create and list_add with kvm->lock

2016-08-12T10:01:27Z

KVM devices were manipulating list data structures without any form of synchronization, and some implementations of the create operations also suffered from a lack of synchronization. Now when we've split the xics create operation into create and init, we can hold the kvm->lock mutex while calling the create operation and when manipulating the devices list. The error path in the generic code gets slightly ugly because we have to take the mutex again and delete the device from the list, but holding the mutex during anon_inode_getfd or releasing/locking the mutex in the common non-error path seemed wrong. Signed-off-by: Christoffer Dall Reviewed-by: Paolo Bonzini Acked-by: Christian Borntraeger Signed-off-by: Radim Krčmář

Merge tag 'kvm-arm-for-4.8-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2016-08-04T11:59:56Z

KVM/ARM Changes for v4.8 - Take 2 Includes GSI routing support to go along with the new VGIC and a small fix that has been cooking in -next for a while.

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2016-08-02T20:11:27Z

Pull KVM updates from Paolo Bonzini: - ARM: GICv3 ITS emulation and various fixes. Removal of the old VGIC implementation. - s390: support for trapping software breakpoints, nested virtualization (vSIE), the STHYI opcode, initial extensions for CPU model support. - MIPS: support for MIPS64 hosts (32-bit guests only) and lots of cleanups, preliminary to this and the upcoming support for hardware virtualization extensions. - x86: support for execute-only mappings in nested EPT; reduced vmexit latency for TSC deadline timer (by about 30%) on Intel hosts; support for more than 255 vCPUs. - PPC: bugfixes. * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (302 commits) KVM: PPC: Introduce KVM_CAP_PPC_HTM MIPS: Select HAVE_KVM for MIPS64_R{2,6} MIPS: KVM: Reset CP0_PageMask during host TLB flush MIPS: KVM: Fix ptr->int cast via KVM_GUEST_KSEGX() MIPS: KVM: Sign extend MFC0/RDHWR results MIPS: KVM: Fix 64-bit big endian dynamic translation MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase MIPS: KVM: Use 64-bit CP0_EBase when appropriate MIPS: KVM: Set CP0_Status.KX on MIPS64 MIPS: KVM: Make entry code MIPS64 friendly MIPS: KVM: Use kmap instead of CKSEG0ADDR() MIPS: KVM: Use virt_to_phys() to get commpage PFN MIPS: Fix definition of KSEGX() for 64-bit KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD kvm: x86: nVMX: maintain internal copy of current VMCS KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures KVM: arm64: vgic-its: Simplify MAPI error handling KVM: arm64: vgic-its: Make vgic_its_cmd_handle_mapi similar to other handlers KVM: arm64: vgic-its: Turn device_id validation into generic ID validation ...

Merge tag 'kvm-arm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into next

2016-07-22T18:27:26Z

KVM/ARM changes for Linux 4.8 - GICv3 ITS emulation - Simpler idmap management that fixes potential TLB conflicts - Honor the kernel protection in HYP mode - Removal of the old vgic implementation

KVM: arm/arm64: Enable irqchip routing

2016-07-22T17:52:01Z

This patch adds compilation and link against irqchip. Main motivation behind using irqchip code is to enable MSI routing code. In the future irqchip routing may also be useful when targeting multiple irqchips. Routing standard callbacks now are implemented in vgic-irqfd: - kvm_set_routing_entry - kvm_set_irq - kvm_set_msi They only are supported with new_vgic code. Both HAVE_KVM_IRQCHIP and HAVE_KVM_IRQ_ROUTING are defined. KVM_CAP_IRQ_ROUTING is advertised and KVM_SET_GSI_ROUTING is allowed. So from now on IRQCHIP routing is enabled and a routing table entry must exist for irqfd injection to succeed for a given SPI. This patch builds a default flat irqchip routing table (gsi=irqchip.pin) covering all the VGIC SPI indexes. This routing table is overwritten by the first first user-space call to KVM_SET_GSI_ROUTING ioctl. MSI routing setup is not yet allowed. Signed-off-by: Eric Auger Signed-off-by: Marc Zyngier

KVM: arm64: vgic-its: Introduce new KVM ITS device

2016-07-18T17:14:35Z

Introduce a new KVM device that represents an ARM Interrupt Translation Service (ITS) controller. Since there can be multiple of this per guest, we can't piggy back on the existing GICv3 distributor device, but create a new type of KVM device. On the KVM_CREATE_DEVICE ioctl we allocate and initialize the ITS data structure and store the pointer in the kvm_device data. Upon an explicit init ioctl from userland (after having setup the MMIO address) we register the handlers with the kvm_io_bus framework. Any reference to an ITS thus has to go via this interface. Signed-off-by: Andre Przywara Reviewed-by: Marc Zyngier Tested-by: Eric Auger Signed-off-by: Marc Zyngier