kernel.git/arch/powerpc/kvm, branch linux-5.10.y

powerpc: fix a file leak in kvm_vcpu_ioctl_enable_cap()

2024-08-19T03:41:05Z

[ Upstream commit b4cf5fc01ce83e5c0bcf3dbb9f929428646b9098 ] missing fdput() on one of the failure exits Fixes: eacc56bb9de3e # v5.2 Signed-off-by: Al Viro Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()

2024-07-27T08:40:19Z

[ Upstream commit a986fa57fd81a1430e00b3c6cf8a325d6f894a63 ] Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group(). It looks up `stt` from tablefd, but then continues to use it after doing fdput() on the returned fd. After the fdput() the tablefd is free to be closed by another thread. The close calls kvm_spapr_tce_release() and then release_spapr_tce_table() (via call_rcu()) which frees `stt`. Although there are calls to rcu_read_lock() in kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent the UAF, because `stt` is used outside the locked regions. With an artifcial delay after the fdput() and a userspace program which triggers the race, KASAN detects the UAF: BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505 CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1 Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV Call Trace: dump_stack_lvl+0xb4/0x108 (unreliable) print_report+0x2b4/0x6ec kasan_report+0x118/0x2b0 __asan_load4+0xb8/0xd0 kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm] kvm_vfio_set_attr+0x524/0xac0 [kvm] kvm_device_ioctl+0x144/0x240 [kvm] sys_ioctl+0x62c/0x1810 system_call_exception+0x190/0x440 system_call_vectored_common+0x15c/0x2ec ... Freed by task 0: ... kfree+0xec/0x3e0 release_spapr_tce_table+0xd4/0x11c [kvm] rcu_core+0x568/0x16a0 handle_softirqs+0x23c/0x920 do_softirq_own_stack+0x6c/0x90 do_softirq_own_stack+0x58/0x90 __irq_exit_rcu+0x218/0x2d0 irq_exit+0x30/0x80 arch_local_irq_restore+0x128/0x230 arch_local_irq_enable+0x1c/0x30 cpuidle_enter_state+0x134/0x5cc cpuidle_enter+0x6c/0xb0 call_cpuidle+0x7c/0x100 do_idle+0x394/0x410 cpu_startup_entry+0x60/0x70 start_secondary+0x3fc/0x410 start_secondary_prolog+0x10/0x14 Fix it by delaying the fdput() until `stt` is no longer in use, which is effectively the entire function. To keep the patch minimal add a call to fdput() at each of the existing return paths. Future work can convert the function to goto or __cleanup style cleanup. With the fix in place the test case no longer triggers the UAF. Reported-by: Al Viro Closes: https://lore.kernel.org/all/20240610024437.GA1464458@ZenIV/ Signed-off-by: Michael Ellerman Link: https://msgid.link/20240614122910.3499489-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

KVM: use __vcalloc for very large allocations

2024-02-23T07:41:55Z

commit 37b2a6510a48ca361ced679f92682b7b7d7d0330 upstream. Allocations whose size is related to the memslot size can be arbitrarily large. Do not use kvzalloc/kvcalloc, as those are limited to "not crazy" sizes that fit in 32 bits. Cc: stable@vger.kernel.org Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls") Reviewed-by: David Hildenbrand Signed-off-by: Paolo Bonzini Signed-off-by: Alexander Ofitserov Signed-off-by: Greg Kroah-Hartman

powerpc: Don't include lppaca.h in paca.h

2023-09-19T10:20:15Z

[ Upstream commit 1aa000667669fa855853decbb1c69e974d8ff716 ] By adding a forward declaration for struct lppaca we can untangle paca.h and lppaca.h. Also move get_lppaca() into lppaca.h for consistency. Add includes of lppaca.h to some files that need it. Signed-off-by: Michael Ellerman Link: https://msgid.link/20230823055317.751786-3-mpe@ellerman.id.au Stable-dep-of: eac030b22ea1 ("powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT") Signed-off-by: Sasha Levin

KVM: PPC: Tick accounting should defer vtime accounting 'til after IRQ handling

2022-09-23T12:16:55Z

[ Upstream commit 235cee162459d96153d63651ce7ff51752528c96 ] Commit 112665286d08 ("KVM: PPC: Book3S HV: Context tracking exit guest context before enabling irqs") moved guest_exit() into the interrupt protected area to avoid wrong context warning (or worse). The problem is that tick-based time accounting has not yet been updated at this point (because it depends on the timer interrupt firing), so the guest time gets incorrectly accounted to system time. To fix the problem, follow the x86 fix in commit 160457140187 ("Defer vtime accounting 'til after IRQ handling"), and allow host IRQs to run before accounting the guest exit time. In the case vtime accounting is enabled, this is not required because TB is used directly for accounting. Before this patch, with CONFIG_TICK_CPU_ACCOUNTING=y in the host and a guest running a kernel compile, the 'guest' fields of /proc/stat are stuck at zero. With the patch they can be observed increasing roughly as expected. Fixes: e233d54d4d97 ("KVM: booke: use __kvm_guest_exit") Fixes: 112665286d08 ("KVM: PPC: Book3S HV: Context tracking exit guest context before enabling irqs") Cc: stable@vger.kernel.org # 5.12+ Signed-off-by: Laurent Vivier [np: only required for tick accounting, add Book3E fix, tweak changelog] Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211027142150.3711582-1-npiggin@gmail.com Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Context tracking exit guest context before enabling irqs

2022-09-23T12:16:55Z

[ Upstream commit 112665286d08c87e66d699e7cba43c1497ad165f ] Interrupts that occur in kernel mode expect that context tracking is set to kernel. Enabling local irqs before context tracking switches from guest to host means interrupts can come in and trigger warnings about wrong context, and possibly worse. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210130130852.2952424-3-npiggin@gmail.com Stable-dep-of: 235cee162459 ("KVM: PPC: Tick accounting should defer vtime accounting 'til after IRQ handling") Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: fix incorrect NULL check on list iterator

2022-06-06T06:42:43Z

commit 300981abddcb13f8f06ad58f52358b53a8096775 upstream. The bug is here: if (!p) return ret; The list iterator value 'p' will *always* be set and non-NULL by list_for_each_entry(), so it is incorrect to assume that the iterator value will be NULL if the list is empty or no element is found. To fix the bug, Use a new value 'iter' as the list iterator, while use the old value 'p' as a dedicated variable to point to the found element. Fixes: dfaa973ae960 ("KVM: PPC: Book3S HV: In H_SVM_INIT_DONE, migrate remaining normal-GFNs to secure-GFNs") Cc: stable@vger.kernel.org # v5.9+ Signed-off-by: Xiaomeng Tong Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220414062103.8153-1-xiam0nd.tong@gmail.com Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Fix TCE handling for VFIO

2022-04-27T11:53:56Z

[ Upstream commit 26a62b750a4e6364b0393562f66759b1494c3a01 ] The LoPAPR spec defines a guest visible IOMMU with a variable page size. Currently QEMU advertises 4K, 64K, 2M, 16MB pages, a Linux VM picks the biggest (16MB). In the case of a passed though PCI device, there is a hardware IOMMU which does not support all pages sizes from the above - P8 cannot do 2MB and P9 cannot do 16MB. So for each emulated 16M IOMMU page we may create several smaller mappings ("TCEs") in the hardware IOMMU. The code wrongly uses the emulated TCE index instead of hardware TCE index in error handling. The problem is easier to see on POWER8 with multi-level TCE tables (when only the first level is preallocated) as hash mode uses real mode TCE hypercalls handlers. The kernel starts using indirect tables when VMs get bigger than 128GB (depends on the max page order). The very first real mode hcall is going to fail with H_TOO_HARD as in the real mode we cannot allocate memory for TCEs (we can in the virtual mode) but on the way out the code attempts to clear hardware TCEs using emulated TCE indexes which corrupts random kernel memory because it_offset==1<<59 is subtracted from those indexes and the resulting index is out of the TCE table bounds. This fixes kvmppc_clear_tce() to use the correct TCE indexes. While at it, this fixes TCE cache invalidation which uses emulated TCE indexes instead of the hardware ones. This went unnoticed as 64bit DMA is used these days and VMs map all RAM in one go and only then do DMA and this is when the TCE cache gets populated. Potentially this could slow down mapping, however normally 16MB emulated pages are backed by 64K hardware pages so it is one write to the "TCE Kill" per 256 updates which is not that bad considering the size of the cache (1024 TCEs or so). Fixes: ca1fc489cfa0 ("KVM: PPC: Book3S: Allow backing bigger guest IOMMU pages with smaller physical pages") Signed-off-by: Alexey Kardashevskiy Tested-by: David Gibson Reviewed-by: Frederic Barrat Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220420050840.328223-1-aik@ozlabs.ru Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Check return value of kvmppc_radix_init

2022-04-08T12:40:14Z

[ Upstream commit 69ab6ac380a00244575de02c406dcb9491bf3368 ] The return of the function is being shadowed by the call to kvmppc_uvmem_init. Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests") Signed-off-by: Fabiano Rosas Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220125155735.1018683-2-farosas@linux.ibm.com Signed-off-by: Sasha Levin

KVM: PPC: Fix vmx/vsx mixup in mmio emulation

2022-04-08T12:40:13Z

[ Upstream commit b99234b918c6e36b9aa0a5b2981e86b6bd11f8e2 ] The MMIO emulation code for vector instructions is duplicated between VSX and VMX. When emulating VMX we should check the VMX copy size instead of the VSX one. Fixes: acc9eb9305fe ("KVM: PPC: Reimplement LOAD_VMX/STORE_VMX instruction ...") Signed-off-by: Fabiano Rosas Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220125215655.1026224-3-farosas@linux.ibm.com Signed-off-by: Sasha Levin