BMC/Intel-BMC/linux.git/arch/x86/kvm, branch dev-5.2

KVM: x86: Don't update RIP or do single-step on faulting emulation

2019-09-06T08:23:37+00:00

commit 75ee23b30dc712d80d2421a9a547e7ab6e379b44 upstream. Don't advance RIP or inject a single-step #DB if emulation signals a fault. This logic applies to all state updates that are conditional on clean retirement of the emulation instruction, e.g. updating RFLAGS was previously handled by commit 38827dbd3fb85 ("KVM: x86: Do not update EFLAGS on faulting emulation"). Not advancing RIP is likely a nop, i.e. ctxt->eip isn't updated with ctxt->_eip until emulation "retires" anyways. Skipping #DB injection fixes a bug reported by Andy Lutomirski where a #UD on SYSCALL due to invalid state with EFLAGS.TF=1 would loop indefinitely due to emulation overwriting the #UD with #DB and thus restarting the bad SYSCALL over and over. Cc: Nadav Amit Cc: stable@vger.kernel.org Reported-by: Andy Lutomirski Fixes: 663f4c61b803 ("KVM: x86: handle singlestep during emulation") Signed-off-by: Sean Christopherson Signed-off-by: Radim Krčmář Signed-off-by: Greg Kroah-Hartman

KVM: x86: hyper-v: don't crash on KVM_GET_SUPPORTED_HV_CPUID when kvm_intel.nested is disabled

2019-09-06T08:23:36+00:00

commit ea1529873ab18c204688cf31746df851c098cbea upstream. If kvm_intel is loaded with nested=0 parameter an attempt to perform KVM_GET_SUPPORTED_HV_CPUID results in OOPS as nested_get_evmcs_version hook in kvm_x86_ops is NULL (we assign it in nested_vmx_hardware_setup() and this only happens in case nested is enabled). Check that kvm_x86_ops->nested_get_evmcs_version is not NULL before calling it. With this, we can remove the stub from svm as it is no longer needed. Cc: Fixes: e2e871ab2f02 ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper") Signed-off-by: Vitaly Kuznetsov Reviewed-by: Jim Mattson Signed-off-by: Radim Krčmář Signed-off-by: Greg Kroah-Hartman

kvm: x86: skip populating logical dest map if apic is not sw enabled

2019-09-06T08:23:36+00:00

commit b14c876b994f208b6b95c222056e1deb0a45de0e upstream. recalculate_apic_map does not santize ldr and it's possible that multiple bits are set. In that case, a previous valid entry can potentially be overwritten by an invalid one. This condition is hit when booting a 32 bit, >8 CPU, RHEL6 guest and then triggering a crash to boot a kdump kernel. This is the sequence of events: 1. Linux boots in bigsmp mode and enables PhysFlat, however, it still writes to the LDR which probably will never be used. 2. However, when booting into kdump, the stale LDR values remain as they are not cleared by the guest and there isn't a apic reset. 3. kdump boots with 1 cpu, and uses Logical Destination Mode but the logical map has been overwritten and points to an inactive vcpu. Signed-off-by: Radim Krcmar Signed-off-by: Bandan Das Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Revert "KVM: x86/mmu: Zap only the relevant pages when removing a memslot"

2019-08-29T06:30:21+00:00

commit d012a06ab1d23178fc6856d8d2161fbcc4dd8ebd upstream. This reverts commit 4e103134b862314dc2f2f18f2fb0ab972adc3f5f. Alex Williamson reported regressions with device assignment with this patch. Even though the bug is probably elsewhere and still latent, this is needed to fix the regression. Fixes: 4e103134b862 ("KVM: x86/mmu: Zap only the relevant pages when removing a memslot", 2019-02-05) Reported-by: Alex Willamson Cc: stable@vger.kernel.org Cc: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: Fix leak vCPU's VMCS value into other pCPU

2019-08-16T08:11:11+00:00

commit 17e433b54393a6269acbcb792da97791fe1592d8 upstream. After commit d73eb57b80b (KVM: Boost vCPUs that are delivering interrupts), a five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting in the VMs after stress testing: INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073) Call Trace: flush_tlb_mm_range+0x68/0x140 tlb_flush_mmu.part.75+0x37/0xe0 tlb_finish_mmu+0x55/0x60 zap_page_range+0x142/0x190 SyS_madvise+0x3cd/0x9c0 system_call_fastpath+0x1c/0x21 swait_active() sustains to be true before finish_swait() is called in kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account by kvm_vcpu_on_spin() loop greatly increases the probability condition kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv is enabled the yield-candidate vCPU's VMCS RVI field leaks(by vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current VMCS. This patch fixes it by checking conservatively a subset of events. Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Christian Borntraeger Cc: Marc Zyngier Cc: stable@vger.kernel.org Fixes: 98f4a1467 (KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop) Signed-off-by: Wanpeng Li Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM/nSVM: properly map nested VMCB

2019-08-16T08:11:08+00:00

commit 8f38302c0be2d2daf3b40f7d2142ec77e35d209e upstream. Commit 8c5fbf1a7231 ("KVM/nSVM: Use the new mapping API for mapping guest memory") broke nested SVM completely: kvm_vcpu_map()'s second parameter is GFN so vmcb_gpa needs to be converted with gpa_to_gfn(), not the other way around. Fixes: 8c5fbf1a7231 ("KVM/nSVM: Use the new mapping API for mapping guest memory") Signed-off-by: Vitaly Kuznetsov Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

x86/cpufeatures: Combine word 11 and 12 into a new scattered features word

2019-08-06T17:08:22+00:00

commit acec0ce081de0c36459eea91647faf99296445a3 upstream It's a waste for the four X86_FEATURE_CQM_* feature bits to occupy two whole feature bits words. To better utilize feature words, re-define word 11 to host scattered features and move the four X86_FEATURE_CQM_* features into Linux defined word 11. More scattered features can be added in word 11 in the future. Rename leaf 11 in cpuid_leafs to CPUID_LNX_4 to reflect it's a Linux-defined leaf. Rename leaf 12 as CPUID_DUMMY which will be replaced by a meaningful name in the next patch when CPUID.7.1:EAX occupies world 12. Maximum number of RMID and cache occupancy scale are retrieved from CPUID.0xf.1 after scattered CQM features are enumerated. Carve out the code into a separate function. KVM doesn't support resctrl now. So it's safe to move the X86_FEATURE_CQM_* features to scattered features word 11 for KVM. Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: Aaron Lewis Cc: Andy Lutomirski Cc: Babu Moger Cc: "Chang S. Bae" Cc: "Sean J Christopherson" Cc: Frederic Weisbecker Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jann Horn Cc: Juergen Gross Cc: Konrad Rzeszutek Wilk Cc: kvm ML Cc: Masahiro Yamada Cc: Masami Hiramatsu Cc: Nadav Amit Cc: Paolo Bonzini Cc: Pavel Tatashin Cc: Peter Feiner Cc: "Peter Zijlstra (Intel)" Cc: "Radim Krčmář" Cc: "Rafael J. Wysocki" Cc: Ravi V Shankar Cc: Sherry Hurwitz Cc: Thomas Gleixner Cc: Thomas Lendacky Cc: x86 Link: https://lkml.kernel.org/r/1560794416-217638-2-git-send-email-fenghua.yu@intel.com Signed-off-by: Greg Kroah-Hartman

KVM: nVMX: Ignore segment base for VMX memory operand when segment not FS or GS

2019-08-06T17:08:09+00:00

[ Upstream commit 6694e48012826351036fd10fc506ca880023e25f ] As reported by Maxime at https://bugzilla.kernel.org/show_bug.cgi?id=204175: In vmx/nested.c::get_vmx_mem_address(), when the guest runs in long mode, the base address of the memory operand is computed with a simple: *ret = s.base + off; This is incorrect, the base applies only to FS and GS, not to the others. Because of that, if the guest uses a VMX instruction based on DS and has a DS.base that is non-zero, KVM wrongfully adds the base to the resulting address. Reported-by: Maxime Villard Reviewed-by: Joao Martins Signed-off-by: Liran Alon Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin

x86: kvm: avoid constant-conversion warning

2019-08-06T17:08:09+00:00

[ Upstream commit a6a6d3b1f867d34ba5bd61aa7bb056b48ca67cff ] clang finds a contruct suspicious that converts an unsigned character to a signed integer and back, causing an overflow: arch/x86/kvm/mmu.c:4605:39: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -205 to 51 [-Werror,-Wconstant-conversion] u8 wf = (pfec & PFERR_WRITE_MASK) ? ~w : 0; ~~ ^~ arch/x86/kvm/mmu.c:4607:38: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -241 to 15 [-Werror,-Wconstant-conversion] u8 uf = (pfec & PFERR_USER_MASK) ? ~u : 0; ~~ ^~ arch/x86/kvm/mmu.c:4609:39: error: implicit conversion from 'int' to 'u8' (aka 'unsigned char') changes value from -171 to 85 [-Werror,-Wconstant-conversion] u8 ff = (pfec & PFERR_FETCH_MASK) ? ~x : 0; ~~ ^~ Add an explicit cast to tell clang that everything works as intended here. Signed-off-by: Arnd Bergmann Link: https://github.com/ClangBuiltLinux/linux/issues/95 Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin

KVM: X86: Fix fpu state crash in kvm guest

2019-07-31T05:24:56+00:00

commit e751732486eb3f159089a64d1901992b1357e7cc upstream. The idea before commit 240c35a37 (which has just been reverted) was that we have the following FPU states: userspace (QEMU) guest --------------------------------------------------------------------------- processor vcpu->arch.guest_fpu >>> KVM_RUN: kvm_load_guest_fpu vcpu->arch.user_fpu processor >>> preempt out vcpu->arch.user_fpu current->thread.fpu >>> preempt in vcpu->arch.user_fpu processor >>> back to userspace >>> kvm_put_guest_fpu processor vcpu->arch.guest_fpu --------------------------------------------------------------------------- With the new lazy model we want to get the state back to the processor when schedule in from current->thread.fpu. Reported-by: Thomas Lambertz Reported-by: anthony Tested-by: anthony Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Thomas Lambertz Cc: anthony Cc: stable@vger.kernel.org Fixes: 5f409e20b (x86/fpu: Defer FPU state load until return to userspace) Signed-off-by: Wanpeng Li [Add a comment in front of the warning. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman