- 25 Nov, 2019 16 commits
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Tamizh chelvam authored
[ Upstream commit bd1d3950 ] When continuously running wifi up/down sequence, the napi poll can be scheduled after the CE buffers being freed by ath10k_pci_flush Steps: In a certain condition, during wifi down below scenario might occur. ath10k_stop->ath10k_hif_stop->napi_schedule->ath10k_pci_flush->napi_poll(napi_synchronize). In the above scenario, CE buffer entries will be freed up and become NULL in ath10k_pci_flush. And the napi_poll has been invoked after the flush process and it will try to get the skb from the CE buffer entry and perform some action on that. Since the CE buffer already cleaned by pci flush this action will create NULL pointer dereference and trigger below kernel panic. Unable to handle kernel NULL pointer dereference at virtual address 0000005c PC is at ath10k_pci_htt_rx_cb+0x64/0x3ec [ath10k_pci] ath10k_pci_htt_rx_cb [ath10k_pci] ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci] ath10k_ce_per_engine_service [ath10k_pci] ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci] ath10k_ce_per_engine_service_any [ath10k_pci] ath10k_pci_napi_poll+0x48/0xec [ath10k_pci] ath10k_pci_napi_poll [ath10k_pci] net_rx_action+0xac/0x160 net_rx_action __do_softirq+0xdc/0x208 __do_softirq irq_exit+0x84/0xe0 irq_exit __handle_domain_irq+0x80/0xa0 __handle_domain_irq gic_handle_irq+0x38/0x5c gic_handle_irq __irq_usr+0x44/0x60 Tested on QCA4019 and firmware version 10.4.3.2.1.1-00010 Signed-off-by:
Tamizh chelvam <tamizhr@codeaurora.org> Signed-off-by:
Kalle Valo <kvalo@codeaurora.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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Eugen Hristev authored
commit fed23c58 upstream. The quirks2 are parsed and set (e.g. from DT) before the quirk for broken HS200 is set in the driver. The driver needs to enable just this flag, not rewrite the whole quirk set. Fixes: 7871aa60 ("mmc: sdhci-of-at91: add quirk for broken HS200") Signed-off-by:
Eugen Hristev <eugen.hristev@microchip.com> Acked-by:
Adrian Hunter <adrian.hunter@intel.com> Cc: stable@vger.kernel.org Signed-off-by:
Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Roman Gushchin authored
commit 0362f326 upstream. An exiting task might belong to an offline cgroup. In this case an attempt to grab a cgroup reference from the task can end up with an infinite loop in hugetlb_cgroup_charge_cgroup(), because neither the cgroup will become online, neither the task will be migrated to a live cgroup. Fix this by switching over to css_tryget(). As css_tryget_online() can't guarantee that the cgroup won't go offline, in most cases the check doesn't make sense. In this particular case users of hugetlb_cgroup_charge_cgroup() are not affected by this change. A similar problem is described by commit 18fa84a2 ("cgroup: Use css_tryget() instead of css_tryget_online() in task_get_css()"). Link: http://lkml.kernel.org/r/20191106225131.3543616-2-guro@fb.comSigned-off-by:
Roman Gushchin <guro@fb.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
Tejun Heo <tj@kernel.org> Reviewed-by:
Shakeel Butt <shakeelb@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Roman Gushchin authored
commit 00d484f3 upstream. We've encountered a rcu stall in get_mem_cgroup_from_mm(): rcu: INFO: rcu_sched self-detected stall on CPU rcu: 33-....: (21000 ticks this GP) idle=6c6/1/0x4000000000000002 softirq=35441/35441 fqs=5017 (t=21031 jiffies g=324821 q=95837) NMI backtrace for cpu 33 <...> RIP: 0010:get_mem_cgroup_from_mm+0x2f/0x90 <...> __memcg_kmem_charge+0x55/0x140 __alloc_pages_nodemask+0x267/0x320 pipe_write+0x1ad/0x400 new_sync_write+0x127/0x1c0 __kernel_write+0x4f/0xf0 dump_emit+0x91/0xc0 writenote+0xa0/0xc0 elf_core_dump+0x11af/0x1430 do_coredump+0xc65/0xee0 get_signal+0x132/0x7c0 do_signal+0x36/0x640 exit_to_usermode_loop+0x61/0xd0 do_syscall_64+0xd4/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The problem is caused by an exiting task which is associated with an offline memcg. We're iterating over and over in the do {} while (!css_tryget_online()) loop, but obviously the memcg won't become online and the exiting task won't be migrated to a live memcg. Let's fix it by switching from css_tryget_online() to css_tryget(). As css_tryget_online() cannot guarantee that the memcg won't go offline, the check is usually useless, except some rare cases when for example it determines if something should be presented to a user. A similar problem is described by commit 18fa84a2 ("cgroup: Use css_tryget() instead of css_tryget_online() in task_get_css()"). Johannes: : The bug aside, it doesn't matter whether the cgroup is online for the : callers. It used to matter when offlining needed to evacuate all charges : from the memcg, and so needed to prevent new ones from showing up, but we : don't care now. Link: http://lkml.kernel.org/r/20191106225131.3543616-1-guro@fb.comSigned-off-by:
Shakeel Butt <shakeeb@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Eric Auger authored
commit 4e7120d7 upstream. For both PASID-based-Device-TLB Invalidate Descriptor and Device-TLB Invalidate Descriptor, the Physical Function Source-ID value is split according to this layout: PFSID[3:0] is set at offset 12 and PFSID[15:4] is put at offset 52. Fix the part laid out at offset 52. Fixes: 0f725561 ("iommu/vt-d: Add definitions for PFSID") Signed-off-by:
Eric Auger <eric.auger@redhat.com> Acked-by:
Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: stable@vger.kernel.org # v4.19+ Acked-by:
Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by:
Joerg Roedel <jroedel@suse.de> Signed-off-by:
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Al Viro authored
commit 762c6968 upstream. We need to get the underlying dentry of parent; sure, absent the races it is the parent of underlying dentry, but there's nothing to prevent losing a timeslice to preemtion in the middle of evaluation of lower_dentry->d_parent->d_inode, having another process move lower_dentry around and have its (ex)parent not pinned anymore and freed on memory pressure. Then we regain CPU and try to fetch ->d_inode from memory that is freed by that point. dentry->d_parent *is* stable here - it's an argument of ->lookup() and we are guaranteed that it won't be moved anywhere until we feed it to d_add/d_splice_alias. So we safely go that way to get to its underlying dentry. Cc: stable@vger.kernel.org # since 2009 or so Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Al Viro authored
commit e72b9dd6 upstream. lower_dentry can't go from positive to negative (we have it pinned), but it *can* go from negative to positive. So fetching ->d_inode into a local variable, doing a blocking allocation, checking that now ->d_inode is non-NULL and feeding the value we'd fetched earlier to a function that won't accept NULL is not a good idea. Cc: stable@vger.kernel.org Signed-off-by:
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James Erwin authored
commit a9c3c4c5 upstream. If an hfi1 card is inserted in a Gen4 systems, the driver will avoid the gen3 speed bump and the card will operate at half speed. This is because the driver avoids the gen3 speed bump when the parent bus speed isn't identical to gen3, 8.0GT/s. This is not compatible with gen4 and newer speeds. Fix by relaxing the test to explicitly look for the lower capability speeds which inherently allows for gen4 and all future speeds. Fixes: 77241056 ("IB/hfi1: add driver files") Link: https://lore.kernel.org/r/20191101192059.106248.1699.stgit@awfm-01.aw.intel.com Cc: <stable@vger.kernel.org> Reviewed-by:
Dennis Dalessandro <dennis.dalessandro@intel.com> Reviewed-by:
Kaike Wan <kaike.wan@intel.com> Signed-off-by:
James Erwin <james.erwin@intel.com> Signed-off-by:
Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by:
Jason Gunthorpe <jgg@mellanox.com> Signed-off-by:
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Chuhong Yuan authored
commit ba60cf9f upstream. The driver forgets to destroy workqueue in remove() similarly to what is done when probe() fails. Add a call to destroy_workqueue() to fix it. Since unregistration will wait for the work to finish, we do not need to cancel/flush the work instance in remove(). Signed-off-by:
Chuhong Yuan <hslester96@gmail.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191114023405.31477-1-hslester96@gmail.comSigned-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
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Lucas Stach authored
commit 549766ac upstream. The driver for F54 just polls the status and doesn't even have a IRQ handler registered. Make sure to disable all F54 IRQs, so we don't crash the kernel on a nonexistent handler. Signed-off-by:
Lucas Stach <l.stach@pengutronix.de> Link: https://lore.kernel.org/r/20191105114402.6009-1-l.stach@pengutronix.de Cc: stable@vger.kernel.org Signed-off-by:
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Lucas Stach authored
commit 003f01c7 upstream. The video buffer used by the queue is a vb2_v4l2_buffer, not a plain vb2_buffer. Using the wrong type causes the allocation of the buffer storage to be too small, causing a out of bounds write when __init_vb2_v4l2_buffer initializes the buffer. Signed-off-by:
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Oliver Neukum authored
commit fa3a5a18 upstream. No timer must be left running when the device goes away. Signed-off-by:
Oliver Neukum <oneukum@suse.com> Reported-and-tested-by: syzbot+b6c55daa701fc389e286@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1573726121.17351.3.camel@suse.comSigned-off-by:
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Henry Lin authored
commit 52869931 upstream. While output urb's snd_complete_urb() is executing, calling prepare_outbound_urb() may cause endpoint stopped before prepare_outbound_urb() returns and result in next urb submitted to stopped endpoint. usb-audio driver cannot re-use it afterwards as the urb is still hold by usb stack. This change checks EP_FLAG_RUNNING flag after prepare_outbound_urb() again to let snd_complete_urb() know the endpoint already stopped and does not submit next urb. Below kind of error will be fixed: [ 213.153103] usb 1-2: timeout: still 1 active urbs on EP #1 [ 213.164121] usb 1-2: cannot submit urb 0, error -16: unknown error Signed-off-by:
Henry Lin <henryl@nvidia.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20191113021420.13377-1-henryl@nvidia.comSigned-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Takashi Iwai authored
commit 167beb17 upstream. A check of the return value from get_cur_mix_raw() is missing at the resolution test code in get_min_max_with_quirks(), which may leave the variable untouched, leading to a random uninitialized value, as detected by syzkaller fuzzer. Add the missing return error check for fixing that. Reported-and-tested-by: syzbot+abe1ab7afc62c6bb6377@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20191109181658.30368-1-tiwai@suse.deSigned-off-by:
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Jouni Hogander authored
[ Upstream commit 3b5a3997 ] Driver/net/can/slcan.c is derived from slip.c. Memory leak was detected by Syzkaller in slcan. Same issue exists in slip.c and this patch is addressing the leak in slip.c. Here is the slcan memory leak trace reported by Syzkaller: BUG: memory leak unreferenced object 0xffff888067f65500 (size 4096): comm "syz-executor043", pid 454, jiffies 4294759719 (age 11.930s) hex dump (first 32 bytes): 73 6c 63 61 6e 30 00 00 00 00 00 00 00 00 00 00 slcan0.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000a06eec0d>] __kmalloc+0x18b/0x2c0 [<0000000083306e66>] kvmalloc_node+0x3a/0xc0 [<000000006ac27f87>] alloc_netdev_mqs+0x17a/0x1080 [<0000000061a996c9>] slcan_open+0x3ae/0x9a0 [<000000001226f0f9>] tty_ldisc_open.isra.1+0x76/0xc0 [<0000000019289631>] tty_set_ldisc+0x28c/0x5f0 [<000000004de5a617>] tty_ioctl+0x48d/0x1590 [<00000000daef496f>] do_vfs_ioctl+0x1c7/0x1510 [<0000000059068dbc>] ksys_ioctl+0x99/0xb0 [<000000009a6eb334>] __x64_sys_ioctl+0x78/0xb0 [<0000000053d0332e>] do_syscall_64+0x16f/0x580 [<0000000021b83b99>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [<000000008ea75434>] 0xfffffffffffffff Cc: "David S. Miller" <davem@davemloft.net> Cc: Oliver Hartkopp <socketcan@hartkopp.net> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by:
Jouni Hogander <jouni.hogander@unikie.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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Oliver Neukum authored
[ Upstream commit a9a51bd7 ] If a malicious device gives a short MAC it can elicit up to 5 bytes of leaked memory out of the driver. We need to check for ETH_ALEN instead. Reported-by: syzbot+a8d4acdad35e6bbca308@syzkaller.appspotmail.com Signed-off-by:
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- 16 Nov, 2019 24 commits
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Greg Kroah-Hartman authored
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Gomez Iglesias, Antonio authored
commit 7f00cc8d upstream. Add the initial ITLB_MULTIHIT documentation. [ tglx: Add it to the index so it gets actually built. ] Signed-off-by:
Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com> Signed-off-by:
Nelson D'Souza <nelson.dsouza@linux.intel.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> [bwh: Backported to 4.9: adjust filenames] Signed-off-by:
Ben Hutchings <ben@decadent.org.uk> Signed-off-by:
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Junaid Shahid authored
commit 1aa9b957 upstream. The page table pages corresponding to broken down large pages are zapped in FIFO order, so that the large page can potentially be recovered, if it is not longer being used for execution. This removes the performance penalty for walking deeper EPT page tables. By default, one large page will last about one hour once the guest reaches a steady state. Signed-off-by:
Junaid Shahid <junaids@google.com> Signed-off-by:
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Junaid Shahid authored
commit c57c8046 upstream. Add a function to create a kernel thread associated with a given VM. In particular, it ensures that the worker thread inherits the priority and cgroups of the calling thread. Signed-off-by:
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Paolo Bonzini authored
commit b8e8c830 upstream. With some Intel processors, putting the same virtual address in the TLB as both a 4 KiB and 2 MiB page can confuse the instruction fetch unit and cause the processor to issue a machine check resulting in a CPU lockup. Unfortunately when EPT page tables use huge pages, it is possible for a malicious guest to cause this situation. Add a knob to mark huge pages as non-executable. When the nx_huge_pages parameter is enabled (and we are using EPT), all huge pages are marked as NX. If the guest attempts to execute in one of those pages, the page is broken down into 4K pages, which are then marked executable. This is not an issue for shadow paging (except nested EPT), because then the host is in control of TLB flushes and the problematic situation cannot happen. With nested EPT, again the nested guest can cause problems shadow and direct EPT is treated in the same way. [ tglx: Fixup default to auto and massage wording a bit ] Originally-by:
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Tyler Hicks authored
commit 731dc9df upstream. A kernel module may need to check the value of the "mitigations=" kernel command line parameter as part of its setup when the module needs to perform software mitigations for a CPU flaw. Uninline and export the helper functions surrounding the cpu_mitigations enum to allow for their usage from a module. Lastly, privatize the enum and cpu_mitigations variable since the value of cpu_mitigations can be checked with the exported helper functions. Signed-off-by:
Tyler Hicks <tyhicks@canonical.com> Signed-off-by:
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Vineela Tummalapalli authored
commit db4d30fb upstream. Some processors may incur a machine check error possibly resulting in an unrecoverable CPU lockup when an instruction fetch encounters a TLB multi-hit in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. The relevant erratum can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=205195 There are other processors affected for which the erratum does not fully disclose the impact. This issue affects both bare-metal x86 page tables and EPT. It can be mitigated by either eliminating the use of large pages or by using careful TLB invalidations when changing the page size in the page tables. Just like Spectre, Meltdown, L1TF and MDS, a new bit has been allocated in MSR_IA32_ARCH_CAPABILITIES (PSCHANGE_MC_NO) and will be set on CPUs which are mitigated against this issue. Signed-off-by:
Vineela Tummalapalli <vineela.tummalapalli@intel.com> Co-developed-by:
Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by:
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Paolo Bonzini authored
commit 9167ab79 upstream. VMX already does so if the host has SMEP, in order to support the combination of CR0.WP=1 and CR4.SMEP=1. However, it is perfectly safe to always do so, and in fact VMX already ends up running with EFER.NXE=1 on old processors that lack the "load EFER" controls, because it may help avoiding a slow MSR write. Removing all the conditionals simplifies the code. SVM does not have similar code, but it should since recent AMD processors do support SMEP. So this patch also makes the code for the two vendors more similar while fixing NPT=0, CR0.WP=1 and CR4.SMEP=1 on AMD processors. Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by:
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Paolo Bonzini authored
commit 335e192a upstream. These are useful in debugging shadow paging. Signed-off-by:
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Ben Hutchings authored
Extracted from commit d3e328f2 "kvm: x86: mmu: Verify that restored PTE has needed perms in fast page fault". Signed-off-by:
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Paolo Bonzini authored
commit e9f2a760 upstream. Note that in such a case it is quite likely that KVM will BUG_ON in __pte_list_remove when the VM is closed. However, there is no immediate risk of memory corruption in the host so a WARN_ON is enough and it lets you gather traces for debugging. Signed-off-by:
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Paolo Bonzini authored
commit d679b326 upstream. After the previous patch, the low bits of the gfn are masked in both FNAME(fetch) and __direct_map, so we do not need to clear them in transparent_hugepage_adjust. Signed-off-by:
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Paolo Bonzini authored
commit 3fcf2d1b upstream. These two functions are basically doing the same thing through kvm_mmu_get_page, link_shadow_page and mmu_set_spte; yet, for historical reasons, their code looks very different. This patch tries to take the best of each and make them very similar, so that it is easy to understand changes that apply to both of them. Signed-off-by:
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Junaid Shahid authored
commit 43fdcda9 upstream. Release the page at the call-site where it was originally acquired. This makes the exit code cleaner for most call sites, since they do not need to duplicate code between success and the failure label. Signed-off-by:
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Junaid Shahid authored
commit 0d9ce162 upstream. It doesn't seem as if there is any particular need for kvm_lock to be a spinlock, so convert the lock to a mutex so that sleepable functions (in particular cond_resched()) can be called while holding it. Signed-off-by:
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Paolo Bonzini authored
commit 9b8ebbdb upstream. The x86 MMU if full of code that returns 0 and 1 for retry/emulate. Use the existing RET_MMIO_PF_RETRY/RET_MMIO_PF_EMULATE enum, renaming it to drop the MMIO part. Signed-off-by:
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Paolo Bonzini authored
commit e08d26f0 upstream. Calling handle_mmio_page_fault() has been unnecessary since commit e9ee956e ("KVM: x86: MMU: Move handle_mmio_page_fault() call to kvm_mmu_page_fault()", 2016-02-22). handle_mmio_page_fault() can now be made static. Signed-off-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
Radim Krčmář <rkrcmar@redhat.com> [bwh: Backported to 4.9: adjust context] Signed-off-by:
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Josh Poimboeuf authored
commit 012206a8 upstream. For new IBRS_ALL CPUs, the Enhanced IBRS check at the beginning of cpu_bugs_smt_update() causes the function to return early, unintentionally skipping the MDS and TAA logic. This is not a problem for MDS, because there appears to be no overlap between IBRS_ALL and MDS-affected CPUs. So the MDS mitigation would be disabled and nothing would need to be done in this function anyway. But for TAA, the TAA_MSG_SMT string will never get printed on Cascade Lake and newer. The check is superfluous anyway: when 'spectre_v2_enabled' is SPECTRE_V2_IBRS_ENHANCED, 'spectre_v2_user' is always SPECTRE_V2_USER_NONE, and so the 'spectre_v2_user' switch statement handles it appropriately by doing nothing. So just remove the check. Fixes: 1b42f017 ("x86/speculation/taa: Add mitigation for TSX Async Abort") Signed-off-by:
Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
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Michal Hocko authored
commit db616173 upstream. There is a general consensus that TSX usage is not largely spread while the history shows there is a non trivial space for side channel attacks possible. Therefore the tsx is disabled by default even on platforms that might have a safe implementation of TSX according to the current knowledge. This is a fair trade off to make. There are, however, workloads that really do benefit from using TSX and updating to a newer kernel with TSX disabled might introduce a noticeable regressions. This would be especially a problem for Linux distributions which will provide TAA mitigations. Introduce config options X86_INTEL_TSX_MODE_OFF, X86_INTEL_TSX_MODE_ON and X86_INTEL_TSX_MODE_AUTO to control the TSX feature. The config setting can be overridden by the tsx cmdline options. [ bp: Text cleanups from Josh. ] Suggested-by:
Borislav Petkov <bpetkov@suse.de> Signed-off-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
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Pawan Gupta authored
commit a7a248c5 upstream. Add the documenation for TSX Async Abort. Include the description of the issue, how to check the mitigation state, control the mitigation, guidance for system administrators. [ bp: Add proper SPDX tags, touch ups by Josh and me. ] Co-developed-by:
Mark Gross <mgross@linux.intel.com> Reviewed-by:
Tony Luck <tony.luck@intel.com> Reviewed-by:
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Pawan Gupta authored
commit 7531a359 upstream. Platforms which are not affected by X86_BUG_TAA may want the TSX feature enabled. Add "auto" option to the TSX cmdline parameter. When tsx=auto disable TSX when X86_BUG_TAA is present, otherwise enable TSX. More details on X86_BUG_TAA can be found here: https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html [ bp: Extend the arg buffer to accommodate "auto\0". ] Signed-off-by:
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Pawan Gupta authored
commit e1d38b63 upstream. Export the IA32_ARCH_CAPABILITIES MSR bit MDS_NO=0 to guests on TSX Async Abort(TAA) affected hosts that have TSX enabled and updated microcode. This is required so that the guests don't complain, "Vulnerable: Clear CPU buffers attempted, no microcode" when the host has the updated microcode to clear CPU buffers. Microcode update also adds support for MSR_IA32_TSX_CTRL which is enumerated by the ARCH_CAP_TSX_CTRL bit in IA32_ARCH_CAPABILITIES MSR. Guests can't do this check themselves when the ARCH_CAP_TSX_CTRL bit is not exported to the guests. In this case export MDS_NO=0 to the guests. When guests have CPUID.MD_CLEAR=1, they deploy MDS mitigation which also mitigates TAA. Signed-off-by:
Neelima Krishnan <neelima.krishnan@intel.com> Reviewed-by:
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Pawan Gupta authored
commit 6608b45a upstream. Add the sysfs reporting file for TSX Async Abort. It exposes the vulnerability and the mitigation state similar to the existing files for the other hardware vulnerabilities. Sysfs file path is: /sys/devices/system/cpu/vulnerabilities/tsx_async_abort Signed-off-by:
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Pawan Gupta authored
commit 1b42f017 upstream. TSX Async Abort (TAA) is a side channel vulnerability to the internal buffers in some Intel processors similar to Microachitectural Data Sampling (MDS). In this case, certain loads may speculatively pass invalid data to dependent operations when an asynchronous abort condition is pending in a TSX transaction. This includes loads with no fault or assist condition. Such loads may speculatively expose stale data from the uarch data structures as in MDS. Scope of exposure is within the same-thread and cross-thread. This issue affects all current processors that support TSX, but do not have ARCH_CAP_TAA_NO (bit 8) set in MSR_IA32_ARCH_CAPABILITIES. On CPUs which have their IA32_ARCH_CAPABILITIES MSR bit MDS_NO=0, CPUID.MD_CLEAR=1 and the MDS mitigation is clearing the CPU buffers using VERW or L1D_FLUSH, there is no additional mitigation needed for TAA. On affected CPUs with MDS_NO=1 this issue can be mitigated by disabling the Transactional Synchronization Extensions (TSX) feature. A new MSR IA32_TSX_CTRL in future and current processors after a microcode update can be used to control the TSX feature. There are two bits in that MSR: * TSX_CTRL_RTM_DISABLE disables the TSX sub-feature Restricted Transactional Memory (RTM). * TSX_CTRL_CPUID_CLEAR clears the RTM enumeration in CPUID. The other TSX sub-feature, Hardware Lock Elision (HLE), is unconditionally disabled with updated microcode but still enumerated as present by CPUID(EAX=7).EBX{bit4}. The second mitigation approach is similar to MDS which is clearing the affected CPU buffers on return to user space and when entering a guest. Relevant microcode update is required for the mitigation to work. More details on this approach can be found here: https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html The TSX feature can be controlled by the "tsx" command line parameter. If it is force-enabled then "Clear CPU buffers" (MDS mitigation) is deployed. The effective mitigation state can be read from sysfs. [ bp: - massage + comments cleanup - s/TAA_MITIGATION_TSX_DISABLE/TAA_MITIGATION_TSX_DISABLED/g - Josh. - remove partial TAA mitigation in update_mds_branch_idle() - Josh. - s/tsx_async_abort_cmdline/tsx_async_abort_parse_cmdline/g ] Signed-off-by:
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