kernel.git/arch/x86/hyperv, branch linux-4.19.y

x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails

2021-11-26T10:36:23Z

commit daf972118c517b91f74ff1731417feb4270625a4 upstream. Check for a valid hv_vp_index array prior to derefencing hv_vp_index when setting Hyper-V's TSC change callback. If Hyper-V setup failed in hyperv_init(), the kernel will still report that it's running under Hyper-V, but will have silently disabled nearly all functionality. BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:set_hv_tscchange_cb+0x15/0xa0 Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08 ... Call Trace: kvm_arch_init+0x17c/0x280 kvm_init+0x31/0x330 vmx_init+0xba/0x13a do_one_initcall+0x41/0x1c0 kernel_init_freeable+0x1f2/0x23b kernel_init+0x16/0x120 ret_from_fork+0x22/0x30 Fixes: 93286261de1b ("x86/hyperv: Reenlightenment notifications support") Cc: stable@vger.kernel.org Cc: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Reviewed-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20211104182239.1302956-2-seanjc@google.com Signed-off-by: Wei Liu Signed-off-by: Greg Kroah-Hartman

x86/hyperv: Protect set_hv_tscchange_cb() against getting preempted

2021-11-26T10:36:07Z

[ Upstream commit 285f68afa8b20f752b0b7194d54980b5e0e27b75 ] The following issue is observed with CONFIG_DEBUG_PREEMPT when KVM loads: KVM: vmx: using Hyper-V Enlightened VMCS BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/488 caller is set_hv_tscchange_cb+0x16/0x80 CPU: 1 PID: 488 Comm: systemd-udevd Not tainted 5.15.0-rc5+ #396 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019 Call Trace: dump_stack_lvl+0x6a/0x9a check_preemption_disabled+0xde/0xe0 ? kvm_gen_update_masterclock+0xd0/0xd0 [kvm] set_hv_tscchange_cb+0x16/0x80 kvm_arch_init+0x23f/0x290 [kvm] kvm_init+0x30/0x310 [kvm] vmx_init+0xaf/0x134 [kvm_intel] ... set_hv_tscchange_cb() can get preempted in between acquiring smp_processor_id() and writing to HV_X64_MSR_REENLIGHTENMENT_CONTROL. This is not an issue by itself: HV_X64_MSR_REENLIGHTENMENT_CONTROL is a partition-wide MSR and it doesn't matter which particular CPU will be used to receive reenlightenment notifications. The only real problem can (in theory) be observed if the CPU whose id was acquired with smp_processor_id() goes offline before we manage to write to the MSR, the logic in hv_cpu_die() won't be able to reassign it correctly. Reported-by: Michael Kelley Signed-off-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20211012155005.1613352-1-vkuznets@redhat.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

x86/hyperv: check cpu mask after interrupt has been disabled

2021-01-19T17:22:35Z

commit ad0a6bad44758afa3b440c254a24999a0c7e35d5 upstream. We've observed crashes due to an empty cpu mask in hyperv_flush_tlb_others. Obviously the cpu mask in question is changed between the cpumask_empty call at the beginning of the function and when it is actually used later. One theory is that an interrupt comes in between and a code path ends up changing the mask. Move the check after interrupt has been disabled to see if it fixes the issue. Signed-off-by: Wei Liu Cc: stable@kernel.org Link: https://lore.kernel.org/r/20210105175043.28325-1-wei.liu@kernel.org Reviewed-by: Michael Kelley Signed-off-by: Greg Kroah-Hartman

x86/Hyper-V: Report crash data in die() when panic_on_oops is set

2020-04-23T08:30:17Z

[ Upstream commit f3a99e761efa616028b255b4de58e9b5b87c5545 ] When oops happens with panic_on_oops unset, the oops thread is killed by die() and system continues to run. In such case, guest should not report crash register data to host since system still runs. Check panic_on_oops and return directly in hyperv_report_panic() when the function is called in the die() and panic_on_oops is unset. Fix it. Fixes: 7ed4325a44ea ("Drivers: hv: vmbus: Make panic reporting to be more useful") Signed-off-by: Tianyu Lan Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20200406155331.2105-7-Tianyu.Lan@microsoft.com Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

x86/hyperv: Suppress "PCI: Fatal: No config space access function found"

2019-11-20T17:47:43Z

[ Upstream commit 2f285f46240d67060061d153786740d4df53cd78 ] A Generation-2 Linux VM on Hyper-V doesn't have the legacy PCI bus, and users always see the scary warning, which is actually harmless. Suppress it. Signed-off-by: Dexuan Cui Signed-off-by: Thomas Gleixner Reviewed-by: Michael Kelley Cc: "H. Peter Anvin" Cc: KY Srinivasan Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: "devel@linuxdriverproject.org" Cc: Olaf Aepfle Cc: Andy Whitcroft Cc: Jason Wang Cc: Vitaly Kuznetsov Cc: Marcelo Cerri Cc: Josh Poulson Link: https://lkml.kernel.org/r/

x86/hyper-v: Fix overflow bug in fill_gva_list()

2019-09-21T05:17:13Z

[ Upstream commit 4030b4c585c41eeefec7bd20ce3d0e100a0f2e4d ] When the 'start' parameter is >= 0xFF000000 on 32-bit systems, or >= 0xFFFFFFFF'FF000000 on 64-bit systems, fill_gva_list() gets into an infinite loop. With such inputs, 'cur' overflows after adding HV_TLB_FLUSH_UNIT and always compares as less than end. Memory is filled with guest virtual addresses until the system crashes. Fix this by never incrementing 'cur' to be larger than 'end'. Reported-by: Jong Hyun Park Signed-off-by: Tianyu Lan Reviewed-by: Michael Kelley Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 2ffd9e33ce4a ("x86/hyper-v: Use hypercall for remote TLB flush") Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

x86/hyperv: Prevent potential NULL pointer dereference

2019-04-20T07:15:59Z

[ Upstream commit 534c89c22e26b183d838294f0937ee092c82ad3a ] The page allocation in hv_cpu_init() can fail, but the code does not have a check for that. Add a check and return -ENOMEM when the allocation fails. [ tglx: Massaged changelog ] Signed-off-by: Kangjie Lu Signed-off-by: Thomas Gleixner Reviewed-by: Mukesh Ojha Acked-by: "K. Y. Srinivasan" Cc: pakki001@umn.edu Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Sasha Levin Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: linux-hyperv@vger.kernel.org Link: https://lkml.kernel.org/r/20190314054651.1315-1-kjlu@umn.edu Signed-off-by: Sasha Levin

x86/hyperv: Fix kernel panic when kexec on HyperV

2019-04-05T20:32:57Z

[ Upstream commit 179fb36abb097976997f50733d5b122a29158cba ] After commit 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments"), kexec fails with a kernel panic: kexec_core: Starting new kernel BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v3.0 03/02/2018 RIP: 0010:0xffffc9000001d000 Call Trace: ? __send_ipi_mask+0x1c6/0x2d0 ? hv_send_ipi_mask_allbutself+0x6d/0xb0 ? mp_save_irq+0x70/0x70 ? __ioapic_read_entry+0x32/0x50 ? ioapic_read_entry+0x39/0x50 ? clear_IO_APIC_pin+0xb8/0x110 ? native_stop_other_cpus+0x6e/0x170 ? native_machine_shutdown+0x22/0x40 ? kernel_kexec+0x136/0x156 That happens if hypercall based IPIs are used because the hypercall page is reset very early upon kexec reboot, but kexec sends IPIs to stop CPUs, which invokes the hypercall and dereferences the unusable page. To fix his, reset hv_hypercall_pg to NULL before the page is reset to avoid any misuse, IPI sending will fall back to the non hypercall based method. This only happens on kexec / kdump so just setting the pointer to NULL is good enough. Fixes: 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments") Signed-off-by: Kairui Song Signed-off-by: Thomas Gleixner Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Sasha Levin Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Vitaly Kuznetsov Cc: Dave Young Cc: devel@linuxdriverproject.org Link: https://lkml.kernel.org/r/20190306111827.14131-1-kasong@redhat.com Signed-off-by: Sasha Levin

x86/hyper-v: rename ipi_arg_{ex,non_ex} structures

2018-09-19T22:51:42Z

These structures are going to be used from KVM code so let's make their names reflect their Hyper-V origin. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Roman Kagan Acked-by: K. Y. Srinivasan Signed-off-by: Paolo Bonzini

x86/mm: Only use tlb_remove_table() for paravirt

2018-08-23T18:56:31Z

If we don't use paravirt; don't play unnecessary and complicated games to free page-tables. Suggested-by: Linus Torvalds Signed-off-by: Peter Zijlstra (Intel) Acked-by: Rik van Riel Signed-off-by: Linus Torvalds