user/sven/linux.git/Documentation, branch v4.9.313

arm64: Add silicon-errata.txt entry for ARM erratum 1188873

2022-04-12T05:52:15Z

commit e03a4e5bb7430f9294c12f02c69eb045d010e942 upstream. Document that we actually work around ARM erratum 1188873 Fixes: 95b861a4a6d9 ("arm64: arch_timer: Add workaround for ARM erratum 1188873") Signed-off-by: Marc Zyngier Signed-off-by: Catalin Marinas Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman

clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter

2022-04-12T05:52:14Z

commit 5444ea6a7f46276876e94ecf8d44615af1ef22f7 upstream. Having a command line option to flip the errata handling for a particular erratum is a little bit unusual, and it's vastly superior to pass this in the DT. By common consensus, it's best to kill off the command line parameter. Signed-off-by: Ding Tianhong [Mark: split patch, reword commit message] Signed-off-by: Mark Rutland Acked-by: Daniel Lezcano Signed-off-by: Daniel Lezcano Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman

x86/speculation: Update link to AMD speculation whitepaper

2022-03-11T09:03:31Z

commit e9b6013a7ce31535b04b02ba99babefe8a8599fa upstream. Update the link to the "Software Techniques for Managing Speculation on AMD Processors" whitepaper. Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov [bwh: Backported to 4.9: adjust filename] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

Documentation/hw-vuln: Update spectre doc

2022-03-11T09:03:31Z

commit 5ad3eb1132453b9795ce5fd4572b1c18b292cca9 upstream. Update the doc with the new fun. [ bp: Massage commit message. ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Thomas Gleixner [fllinden@amazon.com: backported to 4.19] Signed-off-by: Frank van der Linden [bwh: Backported to 4.9: adjust filenames] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

Documentation: refer to config RANDOMIZE_BASE for kernel address-space randomization

2022-03-11T09:03:30Z

commit 82ca67321f55a8d1da6ac3ed611da3c32818bb37 upstream. The config RANDOMIZE_SLAB does not exist, the authors probably intended to refer to the config RANDOMIZE_BASE, which provides kernel address-space randomization. They probably just confused SLAB with BASE (these two four-letter words coincidentally share three common letters), as they also point out the config SLAB_FREELIST_RANDOM as further randomization within the same sentence. Fix the reference of the config for kernel address-space randomization to the config that provides that. Fixes: 6e88559470f5 ("Documentation: Add section about CPU vulnerabilities for Spectre") Signed-off-by: Lukas Bulwahn Link: https://lore.kernel.org/r/20211230171940.27558-1-lukas.bulwahn@gmail.com Signed-off-by: Jonathan Corbet [bwh: Backported to 4.9: adjust filename] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

Documentation: Add swapgs description to the Spectre v1 documentation

2022-03-11T09:03:30Z

commit 4c92057661a3412f547ede95715641d7ee16ddac upstream. Add documentation to the Spectre document about the new swapgs variant of Spectre v1. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner [bwh: Backported to 4.9: adjust filename] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

Documentation: Add section about CPU vulnerabilities for Spectre

2022-03-11T09:03:30Z

commit 6e88559470f581741bcd0f2794f9054814ac9740 upstream. Add documentation for Spectre vulnerability and the mitigation mechanisms: - Explain the problem and risks - Document the mitigation mechanisms - Document the command line controls - Document the sysfs files Co-developed-by: Andi Kleen Signed-off-by: Andi Kleen Co-developed-by: Tim Chen Signed-off-by: Tim Chen Reviewed-by: Randy Dunlap Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet [bwh: Backported to 4.9: - Drop chnages in spec_ctrl.rst, which is a plain-text document here - Adjust filenames and references to spec_ctrl.rst] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

bpf: Add kconfig knob for disabling unpriv bpf by default

2022-02-16T11:43:54Z

commit 08389d888287c3823f80b0216766b71e17f0aba5 upstream. Add a kconfig knob which allows for unprivileged bpf to be disabled by default. If set, the knob sets /proc/sys/kernel/unprivileged_bpf_disabled to value of 2. This still allows a transition of 2 -> {0,1} through an admin. Similarly, this also still keeps 1 -> {1} behavior intact, so that once set to permanently disabled, it cannot be undone aside from a reboot. We've also added extra2 with max of 2 for the procfs handler, so that an admin still has a chance to toggle between 0 <-> 2. Either way, as an additional alternative, applications can make use of CAP_BPF that we added a while ago. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/74ec548079189e4e4dffaeb42b8987bb3c852eee.1620765074.git.daniel@iogearbox.net [fllinden@amazon.com: backported to 4.9] Signed-off-by: Frank van der Linden Signed-off-by: Greg Kroah-Hartman

KVM: X86: MMU: Use the correct inherited permissions to get shadow page

2022-01-29T09:15:58Z

commit b1bd5cba3306691c771d558e94baa73e8b0b96b7 upstream. When computing the access permissions of a shadow page, use the effective permissions of the walk up to that point, i.e. the logic AND of its parents' permissions. Two guest PxE entries that point at the same table gfn need to be shadowed with different shadow pages if their parents' permissions are different. KVM currently uses the effective permissions of the last non-leaf entry for all non-leaf entries. Because all non-leaf SPTEs have full ("uwx") permissions, and the effective permissions are recorded only in role.access and merged into the leaves, this can lead to incorrect reuse of a shadow page and eventually to a missing guest protection page fault. For example, here is a shared pagetable: pgd[] pud[] pmd[] virtual address pointers /->pmd1(u--)->pte1(uw-)->page1 <- ptr1 (u--) /->pud1(uw-)--->pmd2(uw-)->pte2(uw-)->page2 <- ptr2 (uw-) pgd-| (shared pmd[] as above) \->pud2(u--)--->pmd1(u--)->pte1(uw-)->page1 <- ptr3 (u--) \->pmd2(uw-)->pte2(uw-)->page2 <- ptr4 (u--) pud1 and pud2 point to the same pmd table, so: - ptr1 and ptr3 points to the same page. - ptr2 and ptr4 points to the same page. (pud1 and pud2 here are pud entries, while pmd1 and pmd2 here are pmd entries) - First, the guest reads from ptr1 first and KVM prepares a shadow page table with role.access=u--, from ptr1's pud1 and ptr1's pmd1. "u--" comes from the effective permissions of pgd, pud1 and pmd1, which are stored in pt->access. "u--" is used also to get the pagetable for pud1, instead of "uw-". - Then the guest writes to ptr2 and KVM reuses pud1 which is present. The hypervisor set up a shadow page for ptr2 with pt->access is "uw-" even though the pud1 pmd (because of the incorrect argument to kvm_mmu_get_page in the previous step) has role.access="u--". - Then the guest reads from ptr3. The hypervisor reuses pud1's shadow pmd for pud2, because both use "u--" for their permissions. Thus, the shadow pmd already includes entries for both pmd1 and pmd2. - At last, the guest writes to ptr4. This causes no vmexit or pagefault, because pud1's shadow page structures included an "uw-" page even though its role.access was "u--". Any kind of shared pagetable might have the similar problem when in virtual machine without TDP enabled if the permissions are different from different ancestors. In order to fix the problem, we change pt->access to be an array, and any access in it will not include permissions ANDed from child ptes. The test code is: https://lore.kernel.org/kvm/20210603050537.19605-1-jiangshanlai@gmail.com/ Remember to test it with TDP disabled. The problem had existed long before the commit 41074d07c78b ("KVM: MMU: Fix inherited permissions for emulated guest pte updates"), and it is hard to find which is the culprit. So there is no fixes tag here. Signed-off-by: Lai Jiangshan Message-Id: <20210603052455.21023-1-jiangshanlai@gmail.com> Cc: stable@vger.kernel.org Fixes: cea0f0e7ea54 ("[PATCH] KVM: MMU: Shadow page table caching") Signed-off-by: Paolo Bonzini [bwh: Backported to 4.9: - Keep passing vcpu argument to gpte_access functions - Adjust filenames, context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

rbtree: cache leftmost node internally

2022-01-27T07:47:42Z

commit cd9e61ed1eebbcd5dfad59475d41ec58d9b64b6a upstream. Patch series "rbtree: Cache leftmost node internally", v4. A series to extending rbtrees to internally cache the leftmost node such that we can have fast overlap check optimization for all interval tree users[1]. The benefits of this series are that: (i) Unify users that do internal leftmost node caching. (ii) Optimize all interval tree users. (iii) Convert at least two new users (epoll and procfs) to the new interface. This patch (of 16): Red-black tree semantics imply that nodes with smaller or greater (or equal for duplicates) keys always be to the left and right, respectively. For the kernel this is extremely evident when considering our rb_first() semantics. Enabling lookups for the smallest node in the tree in O(1) can save a good chunk of cycles in not having to walk down the tree each time. To this end there are a few core users that explicitly do this, such as the scheduler and rtmutexes. There is also the desire for interval trees to have this optimization allowing faster overlap checking. This patch introduces a new 'struct rb_root_cached' which is just the root with a cached pointer to the leftmost node. The reason why the regular rb_root was not extended instead of adding a new structure was that this allows the user to have the choice between memory footprint and actual tree performance. The new wrappers on top of the regular rb_root calls are: - rb_first_cached(cached_root) -- which is a fast replacement for rb_first. - rb_insert_color_cached(node, cached_root, new) - rb_erase_cached(node, cached_root) In addition, augmented cached interfaces are also added for basic insertion and deletion operations; which becomes important for the interval tree changes. With the exception of the inserts, which adds a bool for updating the new leftmost, the interfaces are kept the same. To this end, porting rb users to the cached version becomes really trivial, and keeping current rbtree semantics for users that don't care about the optimization requires zero overhead. Link: http://lkml.kernel.org/r/20170719014603.19029-2-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Reviewed-by: Jan Kara Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman