kernel.git/arch/powerpc/kvm, branch linux-4.14.y

KVM: PPC: Book3S: Fix H_RTAS rets buffer overflow

2021-07-28T09:12:19Z

commit f62f3c20647ebd5fb6ecb8f0b477b9281c44c10a upstream. The kvmppc_rtas_hcall() sets the host rtas_args.rets pointer based on the rtas_args.nargs that was provided by the guest. That guest nargs value is not range checked, so the guest can cause the host rets pointer to be pointed outside the args array. The individual rtas function handlers check the nargs and nrets values to ensure they are correct, but if they are not, the handlers store a -3 (0xfffffffd) failure indication in rets[0] which corrupts host memory. Fix this by testing up front whether the guest supplied nargs and nret would exceed the array size, and fail the hcall directly without storing a failure indication to rets[0]. Also expand on a comment about why we kill the guest and try not to return errors directly if we have a valid rets[0] pointer. Fixes: 8e591cb72047 ("KVM: PPC: Book3S: Add infrastructure to implement kernel-side RTAS calls") Cc: stable@vger.kernel.org # v3.10+ Reported-by: Alexey Kardashevskiy Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S PR: Free shared page if mmu initialization fails

2020-02-14T21:32:16Z

commit cb10bf9194f4d2c5d830eddca861f7ca0fecdbb4 upstream. Explicitly free the shared page if kvmppc_mmu_init() fails during kvmppc_core_vcpu_create(), as the page is freed only in kvmppc_core_vcpu_free(), which is not reached via kvm_vcpu_uninit(). Fixes: 96bc451a15329 ("KVM: PPC: Introduce shared page") Cc: stable@vger.kernel.org Reviewed-by: Greg Kurz Signed-off-by: Sean Christopherson Acked-by: Paul Mackerras Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Uninit vCPU if vcore creation fails

2020-02-14T21:32:16Z

commit 1a978d9d3e72ddfa40ac60d26301b154247ee0bc upstream. Call kvm_vcpu_uninit() if vcore creation fails to avoid leaking any resources allocated by kvm_vcpu_init(), i.e. the vcpu->run page. Fixes: 371fefd6f2dc4 ("KVM: PPC: Allow book3s_hv guests to use SMT processor modes") Cc: stable@vger.kernel.org Reviewed-by: Greg Kurz Signed-off-by: Sean Christopherson Acked-by: Paul Mackerras Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Release all hardware TCE tables attached to a group

2020-01-27T13:46:19Z

[ Upstream commit a67614cc05a5052b265ea48196dab2fce11f5f2e ] The SPAPR TCE KVM device references all hardware IOMMU tables assigned to some IOMMU group to ensure that in-kernel KVM acceleration of H_PUT_TCE can work. The tables are references when an IOMMU group gets registered with the VFIO KVM device by the KVM_DEV_VFIO_GROUP_ADD ioctl; KVM_DEV_VFIO_GROUP_DEL calls into the dereferencing code in kvm_spapr_tce_release_iommu_group() which walks through the list of LIOBNs, finds a matching IOMMU table and calls kref_put() when found. However that code stops after the very first successful derefencing leaving other tables referenced till the SPAPR TCE KVM device is destroyed which normally happens on guest reboot or termination so if we do hotplug and unplug in a loop, we are leaking IOMMU tables here. This removes a premature return to let kvm_spapr_tce_release_iommu_group() find and dereference all attached tables. Fixes: 121f80ba68f ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO") Signed-off-by: Alexey Kardashevskiy Signed-off-by: Paul Mackerras Signed-off-by: Sasha Levin

KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel

2019-12-01T08:14:36Z

commit af2e8c68b9c5403f77096969c516f742f5bb29e0 upstream. On some systems that are vulnerable to Spectre v2, it is up to software to flush the link stack (return address stack), in order to protect against Spectre-RSB. When exiting from a guest we do some house keeping and then potentially exit to C code which is several stack frames deep in the host kernel. We will then execute a series of returns without preceeding calls, opening up the possiblity that the guest could have poisoned the link stack, and direct speculative execution of the host to a gadget of some sort. To prevent this we add a flush of the link stack on exit from a guest. Signed-off-by: Michael Ellerman [dja: straightforward backport to v4.14] Signed-off-by: Daniel Axtens Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S PR: Exiting split hack mode needs to fixup both PC and LR

2019-11-24T07:23:07Z

[ Upstream commit 1006284c5e411872333967b1970c2ca46a9e225f ] When an OS (currently only classic Mac OS) is running in KVM-PR and makes a linked jump from code with split hack addressing enabled into code that does not, LR is not correctly updated and reflects the previously munged PC. To fix this, this patch undoes the address munge when exiting split hack mode so that code relying on LR being a proper address will now execute. This does not affect OS X or other operating systems running on KVM-PR. Signed-off-by: Cameron Kaiser Signed-off-by: Paul Mackerras Signed-off-by: Sasha Levin

KVM: PPC: Inform the userspace about TCE update failures

2019-11-24T07:22:57Z

[ Upstream commit f7960e299f13f069d6f3d4e157d91bfca2669677 ] We return H_TOO_HARD from TCE update handlers when we think that the next handler (realmode -> virtual mode -> user mode) has a chance to handle the request; H_HARDWARE/H_CLOSED otherwise. This changes the handlers to return H_TOO_HARD on every error giving the userspace an opportunity to handle any request or at least log them all. Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc/mm: Fixup tlbie vs mtpidr/mtlpidr ordering issue on POWER9

2019-11-10T10:25:42Z

commit 047e6575aec71d75b765c22111820c4776cd1c43 upstream. On POWER9, under some circumstances, a broadcast TLB invalidation will fail to invalidate the ERAT cache on some threads when there are parallel mtpidr/mtlpidr happening on other threads of the same core. This can cause stores to continue to go to a page after it's unmapped. The workaround is to force an ERAT flush using PID=0 or LPID=0 tlbie flush. This additional TLB flush will cause the ERAT cache invalidation. Since we are using PID=0 or LPID=0, we don't get filtered out by the TLB snoop filtering logic. We need to still follow this up with another tlbie to take care of store vs tlbie ordering issue explained in commit: a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on POWER9"). The presence of ERAT cache implies we can still get new stores and they may miss store queue marking flush. Cc: stable@vger.kernel.org # v4.14 Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190924035254.24612-3-aneesh.kumar@linux.ibm.com [sandipan: Backported to v4.14] Signed-off-by: Sandipan Das Signed-off-by: Greg Kroah-Hartman

powerpc/book3s64/radix: Rename CPU_FTR_P9_TLBIE_BUG feature flag

2019-11-10T10:25:42Z

commit 09ce98cacd51fcd0fa0af2f79d1e1d3192f4cbb0 upstream. Rename the #define to indicate this is related to store vs tlbie ordering issue. In the next patch, we will be adding another feature flag that is used to handles ERAT flush vs tlbie ordering issue. Cc: stable@vger.kernel.org # v4.14 Fixes: a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on POWER9") Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190924035254.24612-2-aneesh.kumar@linux.ibm.com [sandipan: Backported to v4.14] Signed-off-by: Sandipan Das Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Fixup tlbie vs store ordering issue on POWER9

2019-11-10T10:25:41Z

commit a5d4b5891c2f1f865a2def1eb0030f534e77ff86 upstream. On POWER9, under some circumstances, a broadcast TLB invalidation might complete before all previous stores have drained, potentially allowing stale stores from becoming visible after the invalidation. This works around it by doubling up those TLB invalidations which was verified by HW to be sufficient to close the risk window. This will be documented in a yet-to-be-published errata. Cc: stable@vger.kernel.org # v4.14 Fixes: 1a472c9dba6b ("powerpc/mm/radix: Add tlbflush routines") Signed-off-by: Aneesh Kumar K.V [mpe: Enable the feature in the DT CPU features code for all Power9, rename the feature to CPU_FTR_P9_TLBIE_BUG per benh.] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20180323045627.16800-3-aneesh.kumar@linux.vnet.ibm.com/ [sandipan: Backported to v4.14] Signed-off-by: Sandipan Das Signed-off-by: Greg Kroah-Hartman