- 17 10月, 2018 7 次提交
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由 Sean Christopherson 提交于
An invalid EPTP causes a VMFail(VMXERR_ENTRY_INVALID_CONTROL_FIELD), not a VMExit. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: NJim Mattson <jmattson@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Invalid host state related to loading EFER on VMExit causes a VMFail(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD), not a VMExit. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: NJim Mattson <jmattson@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Jim Mattson 提交于
When bit 3 (corresponding to CR0.TS) of the VMCS12 cr0_guest_host_mask field is clear, the VMCS12 guest_cr0 field does not necessarily hold the current value of the L2 CR0.TS bit, so the code that checked for L2's CR0.TS bit being set was incorrect. Moreover, I'm not sure that the CR0.TS check was adequate. (What if L2's CR0.EM was set, for instance?) Fortunately, lazy FPU has gone away, so L0 has lost all interest in intercepting #NM exceptions. See commit bd7e5b08 ("KVM: x86: remove code for lazy FPU handling"). Therefore, there is no longer any question of which hypervisor gets first dibs. The #NM VM-exit should always be reflected to L1. (Note that the corresponding bit must be set in the VMCS12 exception_bitmap field for there to be an #NM VM-exit at all.) Fixes: ccf9844e ("kvm, vmx: Really fix lazy FPU on nested guest") Reported-by: NAbhiroop Dabral <adabral@paloaltonetworks.com> Signed-off-by: NJim Mattson <jmattson@google.com> Reviewed-by: NPeter Shier <pshier@google.com> Tested-by: NAbhiroop Dabral <adabral@paloaltonetworks.com> Reviewed-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Tianyu Lan 提交于
is_external_interrupt() is not used now and so remove it. Signed-off-by: NLan Tianyu <Tianyu.Lan@microsoft.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Krish Sadhukhan 提交于
Suggested-by: NJim Mattson <jmattson@google.com> Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by: NMark Kanda <mark.kanda@oracle.com> Reviewed-by: NJim Mattson <jmattson@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
A VMEnter that VMFails (as opposed to VMExits) does not touch host state beyond registers that are explicitly noted in the VMFail path, e.g. EFLAGS. Host state does not need to be loaded because VMFail is only signaled for consistency checks that occur before the CPU starts to load guest state, i.e. there is no need to restore any state as nothing has been modified. But in the case where a VMFail is detected by hardware and not by KVM (due to deferring consistency checks to hardware), KVM has already loaded some amount of guest state. Luckily, "loaded" only means loaded to KVM's software model, i.e. vmcs01 has not been modified. So, unwind our software model to the pre-VMEntry host state. Not restoring host state in this VMFail path leads to a variety of failures because we end up with stale data in vcpu->arch, e.g. CR0, CR4, EFER, etc... will all be out of sync relative to vmcs01. Any significant delta in the stale data is all but guaranteed to crash L1, e.g. emulation of SMEP, SMAP, UMIP, WP, etc... will be wrong. An alternative to this "soft" reload would be to load host state from vmcs12 as if we triggered a VMExit (as opposed to VMFail), but that is wildly inconsistent with respect to the VMX architecture, e.g. an L1 VMM with separate VMExit and VMFail paths would explode. Note that this approach does not mean KVM is 100% accurate with respect to VMX hardware behavior, even at an architectural level (the exact order of consistency checks is microarchitecture specific). But 100% emulation accuracy isn't the goal (with this patch), rather the goal is to be consistent in the information delivered to L1, e.g. a VMExit should not fall-through VMENTER, and a VMFail should not jump to HOST_RIP. This technically reverts commit "5af41573 (KVM: nVMX: Fix mmu context after VMLAUNCH/VMRESUME failure)", but retains the core aspects of that patch, just in an open coded form due to the need to pull state from vmcs01 instead of vmcs12. Restoring host state resolves a variety of issues introduced by commit "4f350c6d (kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly)", which remedied the incorrect behavior of treating VMFail like VMExit but in doing so neglected to restore arch state that had been modified prior to attempting nested VMEnter. A sample failure that occurs due to stale vcpu.arch state is a fault of some form while emulating an LGDT (due to emulated UMIP) from L1 after a failed VMEntry to L3, in this case when running the KVM unit test test_tpr_threshold_values in L1. L0 also hits a WARN in this case due to a stale arch.cr4.UMIP. L1: BUG: unable to handle kernel paging request at ffffc90000663b9e PGD 276512067 P4D 276512067 PUD 276513067 PMD 274efa067 PTE 8000000271de2163 Oops: 0009 [#1] SMP CPU: 5 PID: 12495 Comm: qemu-system-x86 Tainted: G W 4.18.0-rc2+ #2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:native_load_gdt+0x0/0x10 ... Call Trace: load_fixmap_gdt+0x22/0x30 __vmx_load_host_state+0x10e/0x1c0 [kvm_intel] vmx_switch_vmcs+0x2d/0x50 [kvm_intel] nested_vmx_vmexit+0x222/0x9c0 [kvm_intel] vmx_handle_exit+0x246/0x15a0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x850/0x1830 [kvm] kvm_vcpu_ioctl+0x3a1/0x5c0 [kvm] do_vfs_ioctl+0x9f/0x600 ksys_ioctl+0x66/0x70 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4f/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 L0: WARNING: CPU: 2 PID: 3529 at arch/x86/kvm/vmx.c:6618 handle_desc+0x28/0x30 [kvm_intel] ... CPU: 2 PID: 3529 Comm: qemu-system-x86 Not tainted 4.17.2-coffee+ #76 Hardware name: Intel Corporation Kabylake Client platform/KBL S RIP: 0010:handle_desc+0x28/0x30 [kvm_intel] ... Call Trace: kvm_arch_vcpu_ioctl_run+0x863/0x1840 [kvm] kvm_vcpu_ioctl+0x3a1/0x5c0 [kvm] do_vfs_ioctl+0x9f/0x5e0 ksys_ioctl+0x66/0x70 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x49/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 5af41573 (KVM: nVMX: Fix mmu context after VMLAUNCH/VMRESUME failure) Fixes: 4f350c6d (kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly) Cc: Jim Mattson <jmattson@google.com> Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim KrÄmář <rkrcmar@redhat.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Jim Mattson 提交于
According to volume 3 of the SDM, bits 63:15 and 12:4 of the exit qualification field for debug exceptions are reserved (cleared to 0). However, the SDM is incorrect about bit 16 (corresponding to DR6.RTM). This bit should be set if a debug exception (#DB) or a breakpoint exception (#BP) occurred inside an RTM region while advanced debugging of RTM transactional regions was enabled. Note that this is the opposite of DR6.RTM, which "indicates (when clear) that a debug exception (#DB) or breakpoint exception (#BP) occurred inside an RTM region while advanced debugging of RTM transactional regions was enabled." There is still an issue with stale DR6 bits potentially being misreported for the current debug exception. DR6 should not have been modified before vectoring the #DB exception, and the "new DR6 bits" should be available somewhere, but it was and they aren't. Fixes: b96fb439 ("KVM: nVMX: fixes to nested virt interrupt injection") Signed-off-by: NJim Mattson <jmattson@google.com> Reviewed-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 13 10月, 2018 5 次提交
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由 Liran Alon 提交于
If L1 uses VPID, it expects TLB to not be flushed on L1<->L2 transitions. However, code currently flushes TLB nonetheless if we didn't allocate a vpid02 for L2. As in this case, vmcs02->vpid == vmcs01->vpid == vmx->vpid. But, if L1 uses EPT, TLB entires populated by L2 are tagged with EPTP02 while TLB entries populated by L1 are tagged with EPTP01. Therefore, we can also avoid TLB flush if L1 uses VPID and EPT. Reviewed-by: NMihai Carabas <mihai.carabas@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
All VPID12s used on a given L1 vCPU is translated to a single VPID02 (vmx->nested.vpid02 or vmx->vpid). Therefore, on L1->L2 VMEntry, we need to invalidate linear and combined mappings tagged by VPID02 in case L1 uses VPID and vmcs12->vpid was changed since last L1->L2 VMEntry. However, current code invalidates the wrong mappings as it calls __vmx_flush_tlb() with invalidate_gpa parameter set to true which will result in invalidating combined and guest-physical mappings tagged with active EPTP which is EPTP01. Similarly, INVVPID emulation have the exact same issue. Fix both issues by just setting invalidate_gpa parameter to false which will result in invalidating linear and combined mappings tagged with given VPID02 as required. Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by: NMark Kanda <mark.kanda@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
In case L0 didn't allocate vmx->nested.vpid02 for L2, vmcs02->vpid is set to vmx->vpid. Consider this case when emulating L1 INVVPID in L0. Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by: NMark Kanda <mark.kanda@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
If L1 and L2 share VPID (because L1 don't use VPID or we haven't allocated a vpid02), we need to flush TLB on L1<->L2 transitions. Before this patch, this TLB flushing was done by vmx_flush_tlb(). If L0 use EPT, this will translate into INVEPT(active_eptp); However, if L1 use EPT, in L1->L2 VMEntry, active EPTP is EPTP01 but TLB entries populated by L2 are tagged with EPTP02. Therefore we should delay vmx_flush_tlb() until active_eptp is EPTP02. To achieve this, instead of directly calling vmx_flush_tlb() we request it to be called by KVM_REQ_TLB_FLUSH which is evaluated after KVM_REQ_LOAD_CR3 which sets the active_eptp to EPTP02 as required. Similarly, on L2->L1 VMExit, active EPTP is EPTP02 but TLB entries populated by L1 are tagged with EPTP01 and therefore we should delay vmx_flush_tlb() until active_eptp is EPTP01. Reviewed-by: NMihai Carabas <mihai.carabas@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
The KVM_GUEST_CR0_MASK macro tracks CR0 bits that are forced to zero by the VMX architecture, i.e. CR0.{NW,CD} must always be zero in the hardware CR0 post-VMXON. Rename the macro to clarify its purpose, be consistent with KVM_VM_CR0_ALWAYS_ON and avoid confusion with the CR0_GUEST_HOST_MASK field. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: NJim Mattson <jmattson@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 04 10月, 2018 3 次提交
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由 Paolo Bonzini 提交于
Commit b5861e5c introduced a check on the interrupt-window and NMI-window CPU execution controls in order to inject an external interrupt vmexit before the first guest instruction executes. However, when APIC virtualization is enabled the host does not need a vmexit in order to inject an interrupt at the next interrupt window; instead, it just places the interrupt vector in RVI and the processor will inject it as soon as possible. Therefore, on machines with APICv it is not enough to check the CPU execution controls: the same scenario can also happen if RVI>vPPR. Fixes: b5861e5cReviewed-by: NNikita Leshchenko <nikita.leshchenko@oracle.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Liran Alon <liran.alon@oracle.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Paolo Bonzini 提交于
As of commit 8d860bbe ("kvm: vmx: Basic APIC virtualization controls have three settings"), KVM will disable VIRTUALIZE_APIC_ACCESSES when a nested guest writes APIC_BASE MSR and kvm-intel.flexpriority=0, whereas previously KVM would allow a nested guest to enable VIRTUALIZE_APIC_ACCESSES so long as it's supported in hardware. That is, KVM now advertises VIRTUALIZE_APIC_ACCESSES to a guest but doesn't (always) allow setting it when kvm-intel.flexpriority=0, and may even initially allow the control and then clear it when the nested guest writes APIC_BASE MSR, which is decidedly odd even if it doesn't cause functional issues. Hide the control completely when the module parameter is cleared. reported-by: NSean Christopherson <sean.j.christopherson@intel.com> Fixes: 8d860bbe ("kvm: vmx: Basic APIC virtualization controls have three settings") Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Return early from vmx_set_virtual_apic_mode() if the processor doesn't support VIRTUALIZE_APIC_ACCESSES or VIRTUALIZE_X2APIC_MODE, both of which reside in SECONDARY_VM_EXEC_CONTROL. This eliminates warnings due to VMWRITEs to SECONDARY_VM_EXEC_CONTROL (VMCS field 401e) failing on processors without secondary exec controls. Remove the similar check for TPR shadowing as it is incorporated in the flexpriority_enabled check and the APIC-related code in vmx_update_msr_bitmap() is further gated by VIRTUALIZE_X2APIC_MODE. Reported-by: NGerhard Wiesinger <redhat@wiesinger.com> Fixes: 8d860bbe ("kvm: vmx: Basic APIC virtualization controls have three settings") Cc: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 01 10月, 2018 3 次提交
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由 Liran Alon 提交于
L2 IA32_BNDCFGS should be updated with vmcs12->guest_bndcfgs only when VM_ENTRY_LOAD_BNDCFGS is specified in vmcs12->vm_entry_controls. Otherwise, L2 IA32_BNDCFGS should be set to vmcs01->guest_bndcfgs which is L1 IA32_BNDCFGS. Reviewed-by: NNikita Leshchenko <nikita.leshchenko@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
Commit a87036ad ("KVM: x86: disable MPX if host did not enable MPX XSAVE features") introduced kvm_mpx_supported() to return true iff MPX is enabled in the host. However, that commit seems to have missed replacing some calls to kvm_x86_ops->mpx_supported() to kvm_mpx_supported(). Complete original commit by replacing remaining calls to kvm_mpx_supported(). Fixes: a87036ad ("KVM: x86: disable MPX if host did not enable MPX XSAVE features") Suggested-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
Before this commit, KVM exposes MPX VMX controls to L1 guest only based on if KVM and host processor supports MPX virtualization. However, these controls should be exposed to guest only in case guest vCPU supports MPX. Without this change, a L1 guest running with kernel which don't have commit 691bd434 ("kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS") asserts in QEMU on the following: qemu-kvm: error: failed to set MSR 0xd90 to 0x0 qemu-kvm: .../qemu-2.10.0/target/i386/kvm.c:1801 kvm_put_msrs: Assertion 'ret == cpu->kvm_msr_buf->nmsrs failed' This is because L1 KVM kvm_init_msr_list() will see that vmx_mpx_supported() (As it only checks MPX VMX controls support) and therefore KVM_GET_MSR_INDEX_LIST IOCTL will include MSR_IA32_BNDCFGS. However, later when L1 will attempt to set this MSR via KVM_SET_MSRS IOCTL, it will fail because !guest_cpuid_has_mpx(vcpu). Therefore, fix the issue by exposing MPX VMX controls to L1 guest only when vCPU supports MPX. Fixes: 36be0b9d ("KVM: x86: Add nested virtualization support for MPX") Reported-by: NEyal Moscovici <eyal.moscovici@oracle.com> Reviewed-by: NNikita Leshchenko <nikita.leshchenko@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 25 9月, 2018 1 次提交
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由 Paolo Bonzini 提交于
KVM has an old optimization whereby accesses to the kernel GS base MSR are trapped when the guest is in 32-bit and not when it is in 64-bit mode. The idea is that swapgs is not available in 32-bit mode, thus the guest has no reason to access the MSR unless in 64-bit mode and 32-bit applications need not pay the price of switching the kernel GS base between the host and the guest values. However, this optimization adds complexity to the code for little benefit (these days most guests are going to be 64-bit anyway) and in fact broke after commit 678e315e ("KVM: vmx: add dedicated utility to access guest's kernel_gs_base", 2018-08-06); the guest kernel GS base can be corrupted across SMIs and UEFI Secure Boot is therefore broken (a secure boot Linux guest, for example, fails to reach the login prompt about half the time). This patch just removes the optimization; the kernel GS base MSR is now never trapped by KVM, similarly to the FS and GS base MSRs. Fixes: 678e315eReviewed-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 20 9月, 2018 7 次提交
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由 Krish Sadhukhan 提交于
According to section "Checks on VMX Controls" in Intel SDM vol 3C, the following check needs to be enforced on vmentry of L2 guests: If the 'enable VPID' VM-execution control is 1, the value of the of the VPID VM-execution control field must not be 0000H. Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by: NMark Kanda <mark.kanda@oracle.com> Reviewed-by: NLiran Alon <liran.alon@oracle.com> Reviewed-by: NJim Mattson <jmattson@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Krish Sadhukhan 提交于
According to section "Checks on VMX Controls" in Intel SDM vol 3C, the following check needs to be enforced on vmentry of L2 guests: - Bits 5:0 of the posted-interrupt descriptor address are all 0. - The posted-interrupt descriptor address does not set any bits beyond the processor's physical-address width. Signed-off-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com> Reviewed-by: NMark Kanda <mark.kanda@oracle.com> Reviewed-by: NLiran Alon <liran.alon@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Reviewed-by: NKarl Heubaum <karl.heubaum@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Liran Alon 提交于
In case L1 do not intercept L2 HLT or enter L2 in HLT activity-state, it is possible for a vCPU to be blocked while it is in guest-mode. According to Intel SDM 26.6.5 Interrupt-Window Exiting and Virtual-Interrupt Delivery: "These events wake the logical processor if it just entered the HLT state because of a VM entry". Therefore, if L1 enters L2 in HLT activity-state and L2 has a pending deliverable interrupt in vmcs12->guest_intr_status.RVI, then the vCPU should be waken from the HLT state and injected with the interrupt. In addition, if while the vCPU is blocked (while it is in guest-mode), it receives a nested posted-interrupt, then the vCPU should also be waken and injected with the posted interrupt. To handle these cases, this patch enhances kvm_vcpu_has_events() to also check if there is a pending interrupt in L2 virtual APICv provided by L1. That is, it evaluates if there is a pending virtual interrupt for L2 by checking RVI[7:4] > VPPR[7:4] as specified in Intel SDM 29.2.1 Evaluation of Pending Interrupts. Note that this also handles the case of nested posted-interrupt by the fact RVI is updated in vmx_complete_nested_posted_interrupt() which is called from kvm_vcpu_check_block() -> kvm_arch_vcpu_runnable() -> kvm_vcpu_running() -> vmx_check_nested_events() -> vmx_complete_nested_posted_interrupt(). Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com> Reviewed-by: NDarren Kenny <darren.kenny@oracle.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Paolo Bonzini 提交于
VMX cannot be enabled under SMM, check it when CR4 is set and when nested virtualization state is restored. This should fix some WARNs reported by syzkaller, mostly around alloc_shadow_vmcs. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
A VMX preemption timer value of '0' is guaranteed to cause a VMExit prior to the CPU executing any instructions in the guest. Use the preemption timer (if it's supported) to trigger immediate VMExit in place of the current method of sending a self-IPI. This ensures that pending VMExit injection to L1 occurs prior to executing any instructions in the guest (regardless of nesting level). When deferring VMExit injection, KVM generates an immediate VMExit from the (possibly nested) guest by sending itself an IPI. Because hardware interrupts are blocked prior to VMEnter and are unblocked (in hardware) after VMEnter, this results in taking a VMExit(INTR) before any guest instruction is executed. But, as this approach relies on the IPI being received before VMEnter executes, it only works as intended when KVM is running as L0. Because there are no architectural guarantees regarding when IPIs are delivered, when running nested the INTR may "arrive" long after L2 is running e.g. L0 KVM doesn't force an immediate switch to L1 to deliver an INTR. For the most part, this unintended delay is not an issue since the events being injected to L1 also do not have architectural guarantees regarding their timing. The notable exception is the VMX preemption timer[1], which is architecturally guaranteed to cause a VMExit prior to executing any instructions in the guest if the timer value is '0' at VMEnter. Specifically, the delay in injecting the VMExit causes the preemption timer KVM unit test to fail when run in a nested guest. Note: this approach is viable even on CPUs with a broken preemption timer, as broken in this context only means the timer counts at the wrong rate. There are no known errata affecting timer value of '0'. [1] I/O SMIs also have guarantees on when they arrive, but I have no idea if/how those are emulated in KVM. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> [Use a hook for SVM instead of leaving the default in x86.c - Paolo] Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Provide a singular location where the VMX preemption timer bit is set/cleared so that future usages of the preemption timer can ensure the VMCS bit is up-to-date without having to modify unrelated code paths. For example, the preemption timer can be used to force an immediate VMExit. Cache the status of the timer to avoid redundant VMREAD and VMWRITE, e.g. if the timer stays armed across multiple VMEnters/VMExits. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
A VMX preemption timer value of '0' at the time of VMEnter is architecturally guaranteed to cause a VMExit prior to the CPU executing any instructions in the guest. This architectural definition is in place to ensure that a previously expired timer is correctly recognized by the CPU as it is possible for the timer to reach zero and not trigger a VMexit due to a higher priority VMExit being signalled instead, e.g. a pending #DB that morphs into a VMExit. Whether by design or coincidence, commit f4124500 ("KVM: nVMX: Fully emulate preemption timer") special cased timer values of '0' and '1' to ensure prompt delivery of the VMExit. Unlike '0', a timer value of '1' has no has no architectural guarantees regarding when it is delivered. Modify the timer emulation to trigger immediate VMExit if and only if the timer value is '0', and document precisely why '0' is special. Do this even if calibration of the virtual TSC failed, i.e. VMExit will occur immediately regardless of the frequency of the timer. Making only '0' a special case gives KVM leeway to be more aggressive in ensuring the VMExit is injected prior to executing instructions in the nested guest, and also eliminates any ambiguity as to why '1' is a special case, e.g. why wasn't the threshold for a "short timeout" set to 10, 100, 1000, etc... Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 08 9月, 2018 1 次提交
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由 Liran Alon 提交于
Consider the case L1 had a IRQ/NMI event until it executed VMLAUNCH/VMRESUME which wasn't delivered because it was disallowed (e.g. interrupts disabled). When L1 executes VMLAUNCH/VMRESUME, L0 needs to evaluate if this pending event should cause an exit from L2 to L1 or delivered directly to L2 (e.g. In case L1 don't intercept EXTERNAL_INTERRUPT). Usually this would be handled by L0 requesting a IRQ/NMI window by setting VMCS accordingly. However, this setting was done on VMCS01 and now VMCS02 is active instead. Thus, when L1 executes VMLAUNCH/VMRESUME we force L0 to perform pending event evaluation by requesting a KVM_REQ_EVENT. Note that above scenario exists when L1 KVM is about to enter L2 but requests an "immediate-exit". As in this case, L1 will disable-interrupts and then send a self-IPI before entering L2. Reviewed-by: NNikita Leshchenko <nikita.leshchenko@oracle.com> Co-developed-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NLiran Alon <liran.alon@oracle.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 30 8月, 2018 3 次提交
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由 Sean Christopherson 提交于
Lack of the kvm_ prefix gives the impression that it's a VMX or SVM specific function, and there's no conflict that prevents adding the kvm_ prefix. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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由 Sean Christopherson 提交于
Re-execution after an emulation decode failure is only intended to handle a case where two or vCPUs race to write a shadowed page, i.e. we should never re-execute an instruction as part of MMIO emulation. As handle_ept_misconfig() is only used for MMIO emulation, it should pass EMULTYPE_NO_REEXECUTE when using the emulator to skip an instr in the fast-MMIO case where VM_EXIT_INSTRUCTION_LEN is invalid. And because the cr2 value passed to x86_emulate_instruction() is only destined for use when retrying or reexecuting, we can simply call emulate_instruction(). Fixes: d391f120 ("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested") Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Cc: stable@vger.kernel.org Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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由 Vitaly Kuznetsov 提交于
nested_run_pending is set 20 lines above and check_vmentry_prereqs()/ check_vmentry_postreqs() don't seem to be resetting it (the later, however, checks it). Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Reviewed-by: NJim Mattson <jmattson@google.com> Reviewed-by: NEduardo Valentin <eduval@amazon.com> Reviewed-by: NKrish Sadhukhan <krish.sadhukhan@oracle.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 22 8月, 2018 3 次提交
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由 Paolo Bonzini 提交于
Two bug fixes: 1) missing entries in the l1d_param array; this can cause a host crash if an access attempts to reach the missing entry. Future-proof the get function against any overflows as well. However, the two entries VMENTER_L1D_FLUSH_EPT_DISABLED and VMENTER_L1D_FLUSH_NOT_REQUIRED must not be accepted by the parse function, so disable them there. 2) invalid values must be rejected even if the CPU does not have the bug, so test for them before checking boot_cpu_has(X86_BUG_L1TF) ... and a small refactoring, since the .cmd field is redundant with the index in the array. Reported-by: NBandan Das <bsd@redhat.com> Cc: stable@vger.kernel.org Fixes: a7b9020bSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Virtualization of Intel SGX depends on Enclave Page Cache (EPC) management that is not yet available in the kernel, i.e. KVM support for exposing SGX to a guest cannot be added until basic support for SGX is upstreamed, which is a WIP[1]. Until SGX is properly supported in KVM, ensure a guest sees expected behavior for ENCLS, i.e. all ENCLS #UD. Because SGX does not have a true software enable bit, e.g. there is no CR4.SGXE bit, the ENCLS instruction can be executed[1] by the guest if SGX is supported by the system. Intercept all ENCLS leafs (via the ENCLS- exiting control and field) and unconditionally inject #UD. [1] https://www.spinics.net/lists/kvm/msg171333.html or https://lkml.org/lkml/2018/7/3/879 [2] A guest can execute ENCLS in the sense that ENCLS will not take an immediate #UD, but no ENCLS will ever succeed in a guest without explicit support from KVM (map EPC memory into the guest), unless KVM has a *very* egregious bug, e.g. accidentally mapped EPC memory into the guest SPTEs. In other words this patch is needed only to prevent the guest from seeing inconsistent behavior, e.g. #GP (SGX not enabled in Feature Control MSR) or #PF (leaf operand(s) does not point at EPC memory) instead of #UD on ENCLS. Intercepting ENCLS is not required to prevent the guest from truly utilizing SGX. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20180814163334.25724-3-sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Yi Wang 提交于
Substitute spaces with tab. No functional changes. Signed-off-by: NYi Wang <wang.yi59@zte.com.cn> Reviewed-by: NJiang Biao <jiang.biao2@zte.com.cn> Message-Id: <1534398159-48509-1-git-send-email-wang.yi59@zte.com.cn> Cc: stable@vger.kernel.org # L1TF Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 21 8月, 2018 1 次提交
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由 Josh Poimboeuf 提交于
These are already defined higher up in the file. Fixes: 7db92e16 ("x86/kvm: Move l1tf setup function") Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/d7ca03ae210d07173452aeed85ffe344301219a5.1534253536.git.jpoimboe@redhat.com
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- 07 8月, 2018 1 次提交
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由 Uros Bizjak 提交于
Remove open-coded uses of set instructions to use CC_SET()/CC_OUT() in arch/x86/kvm/vmx.c. Signed-off-by: NUros Bizjak <ubizjak@gmail.com> [Mark error paths as unlikely while touching this. - Paolo] Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 06 8月, 2018 5 次提交
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由 Sean Christopherson 提交于
The host's FS.base and GS.base rarely change, e.g. ~0.1% of host/guest swaps on my system. Cache the last value written to the VMCS and skip the VMWRITE to the associated VMCS fields when loading host state if the value hasn't changed since the last VMWRITE. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
On a 64-bit host, FS.sel and GS.sel are all but guaranteed to be 0, which in turn means they'll rarely change. Skip the VMWRITE for the associated VMCS fields when loading host state if the selector hasn't changed since the last VMWRITE. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
The HOST_{FS,GS}_BASE fields are guaranteed to be written prior to VMENTER, by way of vmx_prepare_switch_to_guest(). Initialize the fields to zero for 64-bit kernels instead of pulling the base values from their respective MSRs. In addition to eliminating two RDMSRs, vmx_prepare_switch_to_guest() can safely assume the initial value of the fields is zero in all cases. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Make host_state a property of a loaded_vmcs so that it can be used as a cache of the VMCS fields, e.g. to lazily VMWRITE the corresponding VMCS field. Treating host_state as a cache does not work if it's not VMCS specific as the cache would become incoherent when switching between vmcs01 and vmcs02. Move vmcs_host_cr3 and vmcs_host_cr4 into host_state. Explicitly zero out host_state when allocating a new VMCS for a loaded_vmcs. Unlike the pre-existing vmcs_host_cr{3,4} usage, the segment information is not guaranteed to be (re)initialized when running a new nested VMCS, e.g. HOST_FS_BASE is not written in vmx_set_constant_host_state(). Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Sean Christopherson 提交于
Remove fs_reload_needed and gs_ldt_reload_needed from host_state and instead compute whether we need to reload various state at the time we actually do the reload. The state that is tracked by the *_reload_needed variables is not any more volatile than the trackers themselves. Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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