lwn.git/arch/x86/kernel, branch header-removal

x86/fpu: Mask out the invalid MXCSR bits properly

2021-10-16T10:37:50+00:00

This is a fix for the fix (yeah, /facepalm). The correct mask to use is not the negation of the MXCSR_MASK but the actual mask which contains the supported bits in the MXCSR register. Reported and debugged by Ville Syrjälä Fixes: d298b03506d3 ("x86/fpu: Restore the masking out of reserved MXCSR bits") Signed-off-by: Borislav Petkov Tested-by: Ville Syrjälä Tested-by: Ser Olmy Cc: Link: https://lore.kernel.org/r/YWgYIYXLriayyezv@intel.com

Merge tag 'x86_urgent_for_v5.15_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-10-10T17:00:51+00:00

Pull x86 fixes from Borislav Petkov: - A FPU fix to properly handle invalid MXCSR values: 32-bit masks them out due to historical reasons and 64-bit kernels reject them - A fix to clear X86_FEATURE_SMAP when support for is not config-enabled - Three fixes correcting misspelled Kconfig symbols used in code - Two resctrl object cleanup fixes - Yet another attempt at fixing the neverending saga of botched x86 timers, this time because some incredibly smart hardware decides to turn off the HPET timer in a low power state - who cares if the OS is relying on it... - Check the full return value range of an SEV VMGEXIT call to determine whether it returned an error * tag 'x86_urgent_for_v5.15_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Restore the masking out of reserved MXCSR bits x86/Kconfig: Correct reference to MWINCHIP3D x86/platform/olpc: Correct ifdef symbol to intended CONFIG_OLPC_XO15_SCI x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n x86/entry: Correct reference to intended CONFIG_64_BIT x86/resctrl: Fix kfree() of the wrong type in domain_add_cpu() x86/resctrl: Free the ctrlval arrays when domain_setup_mon_state() fails x86/hpet: Use another crystalball to evaluate HPET usability x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0]

x86/fpu: Restore the masking out of reserved MXCSR bits

2021-10-08T09:12:17+00:00

Ser Olmy reported a boot failure: init[1] bad frame in sigreturn frame:(ptrval) ip:b7c9fbe6 sp:bf933310 orax:ffffffff \ in libc-2.33.so[b7bed000+156000] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b CPU: 0 PID: 1 Comm: init Tainted: G W 5.14.9 #1 Hardware name: Hewlett-Packard HP PC/HP Board, BIOS JD.00.06 12/06/2001 Call Trace: dump_stack_lvl dump_stack panic do_exit.cold do_group_exit get_signal arch_do_signal_or_restart ? force_sig_info_to_task ? force_sig exit_to_user_mode_prepare syscall_exit_to_user_mode do_int80_syscall_32 entry_INT80_32 on an old 32-bit Intel CPU: vendor_id : GenuineIntel cpu family : 6 model : 6 model name : Celeron (Mendocino) stepping : 5 microcode : 0x3 Ser bisected the problem to the commit in Fixes. tglx suggested reverting the rejection of invalid MXCSR values which this commit introduced and replacing it with what the old code did - simply masking them out to zero. Further debugging confirmed his suggestion: fpu->state.fxsave.mxcsr: 0xb7be13b4, mxcsr_feature_mask: 0xffbf WARNING: CPU: 0 PID: 1 at arch/x86/kernel/fpu/signal.c:384 __fpu_restore_sig+0x51f/0x540 so restore the original behavior only for 32-bit kernels where you have ancient machines with buggy hardware. For 32-bit programs on 64-bit kernels, user space which supplies wrong MXCSR values is considered malicious so fail the sigframe restoration there. Fixes: 6f9866a166cd ("x86/fpu/signal: Let xrstor handle the features to init") Reported-by: Ser Olmy Signed-off-by: Borislav Petkov Tested-by: Ser Olmy Cc: Link: https://lkml.kernel.org/r/YVtA67jImg3KlBTw@zn.tnic

x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n

2021-10-06T16:46:06+00:00

Commit 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") added a warning if AC is set when in the kernel. Commit 662a0221893a3d ("x86/entry: Fix AC assertion") changed the warning to only fire if the CPU supports SMAP. However, the warning can still trigger on a machine that supports SMAP but where it's disabled in the kernel config and when running the syscall_nt selftest, for example: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 49 at irqentry_enter_from_user_mode CPU: 0 PID: 49 Comm: init Tainted: G T 5.15.0-rc4+ #98 e6202628ee053b4f310759978284bd8bb0ce6905 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:irqentry_enter_from_user_mode ... Call Trace: ? irqentry_enter ? exc_general_protection ? asm_exc_general_protection ? asm_exc_general_protectio IS_ENABLED(CONFIG_X86_SMAP) could be added to the warning condition, but even this would not be enough in case SMAP is disabled at boot time with the "nosmap" parameter. To be consistent with "nosmap" behaviour, clear X86_FEATURE_SMAP when !CONFIG_X86_SMAP. Found using entry-fuzz + satrandconfig. [ bp: Massage commit message. ] Fixes: 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") Fixes: 662a0221893a ("x86/entry: Fix AC assertion") Signed-off-by: Vegard Nossum Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20211003223423.8666-1-vegard.nossum@oracle.com

x86/resctrl: Fix kfree() of the wrong type in domain_add_cpu()

2021-10-06T16:45:27+00:00

Commit in Fixes separated the architecture specific and filesystem parts of the resctrl domain structures. This left the error paths in domain_add_cpu() kfree()ing the memory with the wrong type. This will cause a problem if someone adds a new member to struct rdt_hw_domain meaning d_resctrl is no longer the first member. Fixes: 792e0f6f789b ("x86/resctrl: Split struct rdt_domain") Signed-off-by: James Morse Signed-off-by: Borislav Petkov Acked-by: Reinette Chatre Link: https://lkml.kernel.org/r/20210917165924.28254-1-james.morse@arm.com

x86/resctrl: Free the ctrlval arrays when domain_setup_mon_state() fails

2021-10-06T16:45:21+00:00

domain_add_cpu() is called whenever a CPU is brought online. The earlier call to domain_setup_ctrlval() allocates the control value arrays. If domain_setup_mon_state() fails, the control value arrays are not freed. Add the missing kfree() calls. Fixes: 1bd2a63b4f0de ("x86/intel_rdt/mba_sc: Add initialization support") Fixes: edf6fa1c4a951 ("x86/intel_rdt/cqm: Add RMID (Resource monitoring ID) management") Signed-off-by: James Morse Signed-off-by: Borislav Petkov Acked-by: Reinette Chatre Cc: Link: https://lkml.kernel.org/r/20210917165958.28313-1-james.morse@arm.com

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2021-10-01T18:08:07+00:00

Pull more kvm fixes from Paolo Bonzini: "Small x86 fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: selftests: Ensure all migrations are performed when test is affined KVM: x86: Swap order of CPUID entry "index" vs. "significant flag" checks ptp: Fix ptp_kvm_getcrosststamp issue for x86 ptp_kvm x86/kvmclock: Move this_cpu_pvti into kvmclock.h selftests: KVM: Don't clobber XMM register when read KVM: VMX: Fix a TSX_CTRL_CPUID_CLEAR field mask issue

x86/hpet: Use another crystalball to evaluate HPET usability

2021-10-01T11:38:13+00:00

On recent Intel systems the HPET stops working when the system reaches PC10 idle state. The approach of adding PCI ids to the early quirks to disable HPET on these systems is a whack a mole game which makes no sense. Check for PC10 instead and force disable HPET if supported. The check is overbroad as it does not take ACPI, intel_idle enablement and command line parameters into account. That's fine as long as there is at least PMTIMER available to calibrate the TSC frequency. The decision can be overruled by adding "hpet=force" on the kernel command line. Remove the related early PCI quirks for affected Ice Cake and Coffin Lake systems as they are not longer required. That should also cover all other systems, i.e. Tiger Rag and newer generations, which are most likely affected by this as well. Fixes: Yet another hardware trainwreck Reported-by: Jakub Kicinski Signed-off-by: Thomas Gleixner Tested-by: Jakub Kicinski Reviewed-by: Rafael J. Wysocki Cc: stable@vger.kernel.org Cc: Kai-Heng Feng Cc: Bjorn Helgaas

x86/sev: Return an error on a returned non-zero SW_EXITINFO1[31:0]

2021-10-01T09:14:41+00:00

After returning from a VMGEXIT NAE event, SW_EXITINFO1[31:0] is checked for a value of 1, which indicates an error and that SW_EXITINFO2 contains exception information. However, future versions of the GHCB specification may define new values for SW_EXITINFO1[31:0], so really any non-zero value should be treated as an error. Fixes: 597cfe48212a ("x86/boot/compressed/64: Setup a GHCB-based VC Exception handler") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov Cc: # 5.10+ Link: https://lkml.kernel.org/r/efc772af831e9e7f517f0439b13b41f56bad8784.1633063321.git.thomas.lendacky@amd.com

x86/kvmclock: Move this_cpu_pvti into kvmclock.h

2021-09-30T08:08:01+00:00

There're other modules might use hv_clock_per_cpu variable like ptp_kvm, so move it into kvmclock.h and export the symbol to make it visiable to other modules. Signed-off-by: Zelin Deng Cc: Message-Id: <1632892429-101194-2-git-send-email-zelin.deng@linux.alibaba.com> Signed-off-by: Paolo Bonzini