kernel.git/arch/x86, branch linux-5.13.y

x86/hyperv: fix for unwanted manipulation of sched_clock when TSC marked unstable

2021-09-18T11:41:59Z

[ Upstream commit c445535c3efbfb8cb42d098e624d46ab149664b7 ] Marking TSC as unstable has a side effect of marking sched_clock as unstable when TSC is still being used as the sched_clock. This is not desirable. Hyper-V ultimately uses a paravirtualized clock source that provides a stable scheduler clock even on systems without TscInvariant CPU capability. Hence, mark_tsc_unstable() call should be called _after_ scheduler clock has been changed to the paravirtualized clocksource. This will prevent any unwanted manipulation of the sched_clock. Only TSC will be correctly marked as unstable. Signed-off-by: Ani Sinha Reviewed-by: Michael Kelley Tested-by: Michael Kelley Link: https://lore.kernel.org/r/20210713030522.1714803-1-ani@anisinha.ca Signed-off-by: Wei Liu Signed-off-by: Sasha Levin

xen: fix setting of max_pfn in shared_info

2021-09-18T11:41:44Z

commit 4b511d5bfa74b1926daefd1694205c7f1bcf677f upstream. Xen PV guests are specifying the highest used PFN via the max_pfn field in shared_info. This value is used by the Xen tools when saving or migrating the guest. Unfortunately this field is misnamed, as in reality it is specifying the number of pages (including any memory holes) of the guest, so it is the highest used PFN + 1. Renaming isn't possible, as this is a public Xen hypervisor interface which needs to be kept stable. The kernel will set the value correctly initially at boot time, but when adding more pages (e.g. due to memory hotplug or ballooning) a real PFN number is stored in max_pfn. This is done when expanding the p2m array, and the PFN stored there is even possibly wrong, as it should be the last possible PFN of the just added P2M frame, and not one which led to the P2M expansion. Fix that by setting shared_info->max_pfn to the last possible PFN + 1. Fixes: 98dd166ea3a3c3 ("x86/xen/p2m: hint at the last populated P2M entry") Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Link: https://lore.kernel.org/r/20210730092622.9973-2-jgross@suse.com Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

KVM: nVMX: Unconditionally clear nested.pi_pending on nested VM-Enter

2021-09-15T08:00:58Z

commit f7782bb8d818d8f47c26b22079db10599922787a upstream. Clear nested.pi_pending on nested VM-Enter even if L2 will run without posted interrupts enabled. If nested.pi_pending is left set from a previous L2, vmx_complete_nested_posted_interrupt() will pick up the stale flag and exit to userspace with an "internal emulation error" due the new L2 not having a valid nested.pi_desc. Arguably, vmx_complete_nested_posted_interrupt() should first check for posted interrupts being enabled, but it's also completely reasonable that KVM wouldn't screw up a fundamental flag. Not to mention that the mere existence of nested.pi_pending is a long-standing bug as KVM shouldn't move the posted interrupt out of the IRR until it's actually processed, e.g. KVM effectively drops an interrupt when it performs a nested VM-Exit with a "pending" posted interrupt. Fixing the mess is a future problem. Prior to vmx_complete_nested_posted_interrupt() interpreting a null PI descriptor as an error, this was a benign bug as the null PI descriptor effectively served as a check on PI not being enabled. Even then, the new flow did not become problematic until KVM started checking the result of kvm_check_nested_events(). Fixes: 705699a13994 ("KVM: nVMX: Enable nested posted interrupt processing") Fixes: 966eefb89657 ("KVM: nVMX: Disable vmcs02 posted interrupts if vmcs12 PID isn't mappable") Fixes: 47d3530f86c0 ("KVM: x86: Exit to userspace when kvm_check_nested_events fails") Cc: stable@vger.kernel.org Cc: Jim Mattson Signed-off-by: Sean Christopherson Message-Id: <20210810144526.2662272-1-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: VMX: avoid running vmx_handle_exit_irqoff in case of emulation

2021-09-15T08:00:57Z

commit 81b4b56d4f8130bbb99cf4e2b48082e5b4cfccb9 upstream. If we are emulating an invalid guest state, we don't have a correct exit reason, and thus we shouldn't do anything in this function. Signed-off-by: Maxim Levitsky Message-Id: <20210826095750.1650467-2-mlevitsk@redhat.com> Cc: stable@vger.kernel.org Fixes: 95b5a48c4f2b ("KVM: VMX: Handle NMIs, #MCs and async #PFs in common irqs-disabled fn", 2019-06-18) Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86/mmu: Avoid collision with !PRESENT SPTEs in TDP MMU lpage stats

2021-09-15T08:00:57Z

commit 088acd23526647844aec1c39db4ad02552c86c7b upstream. Factor in whether or not the old/new SPTEs are shadow-present when adjusting the large page stats in the TDP MMU. A modified MMIO SPTE can toggle the page size bit, as bit 7 is used to store the MMIO generation, i.e. is_large_pte() can get a false positive when called on a MMIO SPTE. Ditto for nuking SPTEs with REMOVED_SPTE, which sets bit 7 in its magic value. Opportunistically move the logic below the check to verify at least one of the old/new SPTEs is shadow present. Use is/was_leaf even though is/was_present would suffice. The code generation is roughly equivalent since all flags need to be computed prior to the code in question, and using the *_leaf flags will minimize the diff in a future enhancement to account all pages, i.e. will change the check to "is_leaf != was_leaf". Reviewed-by: David Matlack Reviewed-by: Ben Gardon Fixes: 1699f65c8b65 ("kvm/x86: Fix 'lpages' kvm stat for TDM MMU") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Mingwei Zhang Message-Id: <20210803044607.599629-3-mizhang@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: clamp host mapping level to max_level in kvm_mmu_max_mapping_level

2021-09-15T08:00:57Z

commit ec607a564f70519b340f7eb4cfc0f4a6b55285ac upstream. This change started as a way to make kvm_mmu_hugepage_adjust a bit simpler, but it does fix two bugs as well. One bug is in zapping collapsible PTEs. If a large page size is disallowed but not all of them, kvm_mmu_max_mapping_level will return the host mapping level and the small PTEs will be zapped up to that level. However, if e.g. 1GB are prohibited, we can still zap 4KB mapping and preserve the 2MB ones. This can happen for example when NX huge pages are in use. The second would happen when userspace backs guest memory with a 1gb hugepage but only assign a subset of the page to the guest. 1gb pages would be disallowed by the memslot, but not 2mb. kvm_mmu_max_mapping_level() would fall through to the host_pfn_mapping_level() logic, see the 1gb hugepage, and map the whole thing into the guest. Fixes: 2f57b7051fe8 ("KVM: x86/mmu: Persist gfn_lpage_is_disallowed() to max_level") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Update vCPU's hv_clock before back to guest when tsc_offset is adjusted

2021-09-15T08:00:57Z

commit d9130a2dfdd4b21736c91b818f87dbc0ccd1e757 upstream. When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature especially there's a big tsc warp (like a new vCPU is hot-added into VM which has been up for a long time), tsc_offset is added by a large value then go back to guest. This causes system time jump as tsc_timestamp is not adjusted in the meantime and pvclock monotonic character. To fix this, just notify kvm to update vCPU's guest time before back to guest. Cc: stable@vger.kernel.org Signed-off-by: Zelin Deng Signed-off-by: Paolo Bonzini Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@linux.alibaba.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "KVM: x86: mmu: Add guest physical address check in translate_gpa()"

2021-09-15T08:00:57Z

commit e7177339d7b5f9594b316842122b5fda9513d5e2 upstream. Revert a misguided illegal GPA check when "translating" a non-nested GPA. The check is woefully incomplete as it does not fill in @exception as expected by all callers, which leads to KVM attempting to inject a bogus exception, potentially exposing kernel stack information in the process. WARNING: CPU: 0 PID: 8469 at arch/x86/kvm/x86.c:525 exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525 CPU: 1 PID: 8469 Comm: syz-executor531 Not tainted 5.14.0-rc7-syzkaller #0 RIP: 0010:exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525 Call Trace: x86_emulate_instruction+0xef6/0x1460 arch/x86/kvm/x86.c:7853 kvm_mmu_page_fault+0x2f0/0x1810 arch/x86/kvm/mmu/mmu.c:5199 handle_ept_misconfig+0xdf/0x3e0 arch/x86/kvm/vmx/vmx.c:5336 __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6021 [inline] vmx_handle_exit+0x336/0x1800 arch/x86/kvm/vmx/vmx.c:6038 vcpu_enter_guest+0x2a1c/0x4430 arch/x86/kvm/x86.c:9712 vcpu_run arch/x86/kvm/x86.c:9779 [inline] kvm_arch_vcpu_ioctl_run+0x47d/0x1b20 arch/x86/kvm/x86.c:10010 kvm_vcpu_ioctl+0x49e/0xe50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3652 The bug has escaped notice because practically speaking the GPA check is useless. The GPA check in question only comes into play when KVM is walking guest page tables (or "translating" CR3), and KVM already handles illegal GPA checks by setting reserved bits in rsvd_bits_mask for each PxE, or in the case of CR3 for loading PTDPTRs, manually checks for an illegal CR3. This particular failure doesn't hit the existing reserved bits checks because syzbot sets guest.MAXPHYADDR=1, and IA32 architecture simply doesn't allow for such an absurd MAXPHYADDR, e.g. 32-bit paging doesn't define any reserved PA bits checks, which KVM emulates by only incorporating the reserved PA bits into the "high" bits, i.e. bits 63:32. Simply remove the bogus check. There is zero meaningful value and no architectural justification for supporting guest.MAXPHYADDR < 32, and properly filling the exception would introduce non-trivial complexity. This reverts commit ec7771ab471ba6a945350353617e2e3385d0e013. Fixes: ec7771ab471b ("KVM: x86: mmu: Add guest physical address check in translate_gpa()") Cc: stable@vger.kernel.org Reported-by: syzbot+200c08e88ae818f849ce@syzkaller.appspotmail.com Signed-off-by: Sean Christopherson Message-Id: <20210831164224.1119728-2-seanjc@google.com> Reviewed-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

x86/resctrl: Fix a maybe-uninitialized build warning treated as error

2021-09-15T08:00:57Z

commit 527f721478bce3f49b513a733bacd19d6f34b08c upstream. The recent commit 064855a69003 ("x86/resctrl: Fix default monitoring groups reporting") caused a RHEL build failure with an uninitialized variable warning treated as an error because it removed the default case snippet. The RHEL Makefile uses '-Werror=maybe-uninitialized' to force possibly uninitialized variable warnings to be treated as errors. This is also reported by smatch via the 0day robot. The error from the RHEL build is: arch/x86/kernel/cpu/resctrl/monitor.c: In function ‘__mon_event_count’: arch/x86/kernel/cpu/resctrl/monitor.c:261:12: error: ‘m’ may be used uninitialized in this function [-Werror=maybe-uninitialized] m->chunks += chunks; ^~ The upstream Makefile does not build using '-Werror=maybe-uninitialized'. So, the problem is not seen there. Fix the problem by putting back the default case snippet. [ bp: note that there's nothing wrong with the code and other compilers do not trigger this warning - this is being done just so the RHEL compiler is happy. ] Fixes: 064855a69003 ("x86/resctrl: Fix default monitoring groups reporting") Reported-by: Terry Bowman Reported-by: kernel test robot Signed-off-by: Babu Moger Signed-off-by: Borislav Petkov Reviewed-by: Reinette Chatre Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/162949631908.23903.17090272726012848523.stgit@bmoger-ubuntu Signed-off-by: Greg Kroah-Hartman

perf/x86/amd/ibs: Extend PERF_PMU_CAP_NO_EXCLUDE to IBS Op

2021-09-15T08:00:57Z

commit f11dd0d80555cdc8eaf5cfc9e19c9e198217f9f1 upstream. Commit: 2ff40250691e ("perf/core, arch/x86: Use PERF_PMU_CAP_NO_EXCLUDE for exclusion incapable PMUs") neglected to do so. Fixes: 2ff40250691e ("perf/core, arch/x86: Use PERF_PMU_CAP_NO_EXCLUDE for exclusion incapable PMUs") Signed-off-by: Kim Phillips Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210817221048.88063-2-kim.phillips@amd.com Signed-off-by: Greg Kroah-Hartman