- Aug 06, 2018
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Junaid Shahid authored
When using shadow paging, a CR3 switch in the guest results in a VM Exit. In the common case, that VM exit doesn't require much processing by KVM. However, it does acquire the MMU lock, which can start showing signs of contention under some workloads even on a 2 VCPU VM when the guest is using KPTI. Therefore, we add a fast path that avoids acquiring the MMU lock in the most common cases e.g. when switching back and forth between the kernel and user mode CR3s used by KPTI with no guest page table changes in between. For now, this fast path is implemented only for 64-bit guests and hosts to avoid the handling of PDPTEs, but it can be extended later to 32-bit guests and/or hosts as well. Signed-off-by:
Junaid Shahid <junaids@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Junaid Shahid authored
kvm_mmu_sync_roots() can locklessly check whether a sync is needed and just bail out if it isn't. Signed-off-by:
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Junaid Shahid authored
sync_page() calls set_spte() from a loop across a page table. It would work better if set_spte() left the TLB flushing to its callers, so that sync_page() can aggregate into a single call. Signed-off-by:
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Peter Xu authored
It's never used. Drop it. Signed-off-by:
Peter Xu <peterx@redhat.com> Signed-off-by:
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Liran Alon authored
No functionality change. This is done as a preparation for VMCS shadowing virtualization. Signed-off-by:
Liran Alon <liran.alon@oracle.com> Signed-off-by:
Jim Mattson <jmattson@google.com> Signed-off-by:
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Liran Alon authored
No functionality change. Signed-off-by:
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Liran Alon authored
Expose VMCS shadowing to L1 as a VMX capability of the virtual CPU, whether or not VMCS shadowing is supported by the physical CPU. (VMCS shadowing emulation) Shadowed VMREADs and VMWRITEs from L2 are handled by L0, without a VM-exit to L1. Signed-off-by:
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Liran Alon authored
KVM: nVMX: Do not forward VMREAD/VMWRITE VMExits to L1 if required so by vmcs12 vmread/vmwrite bitmaps This is done as a preparation for VMCS shadowing emulation. Signed-off-by:
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Liran Alon authored
This is done as a preparation to VMCS shadowing emulation. Signed-off-by:
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Paolo Bonzini authored
This includes setting up the shadow VMCS and the secondary execution controls in lib/vmx.c. Signed-off-by: -
Paolo Bonzini authored
The shadow vmcs12 cannot be flushed on KVM_GET_NESTED_STATE, because at that point guest memory is assumed by userspace to be immutable. Capture the cache in vmx_get_nested_state, adding another page at the end if there is an active shadow vmcs12. Signed-off-by: -
Liran Alon authored
This is done is done as a preparation to VMCS shadowing emulation. Signed-off-by:
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Liran Alon authored
Intel SDM considers these checks to be part of "Checks on Guest Non-Register State". Note that it is legal for vmcs->vmcs_link_pointer to be -1ull when VMCS shadowing is enabled. In this case, any VMREAD/VMWRITE to shadowed-field sets the ALU flags for VMfailInvalid (i.e. CF=1). Signed-off-by:
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Liran Alon authored
Signed-off-by:
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Liran Alon authored
Signed-off-by:
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Liran Alon authored
Signed-off-by:
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Liran Alon authored
Signed-off-by:
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Liran Alon authored
No functionality change. This is done as a preparation for VMCS shadowing emulation. Signed-off-by:
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Liran Alon authored
No functionality change. Signed-off-by:
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Paolo Bonzini authored
Signed-off-by: -
Jim Mattson authored
For nested virtualization L0 KVM is managing a bit of state for L2 guests, this state can not be captured through the currently available IOCTLs. In fact the state captured through all of these IOCTLs is usually a mix of L1 and L2 state. It is also dependent on whether the L2 guest was running at the moment when the process was interrupted to save its state. With this capability, there are two new vcpu ioctls: KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE. These can be used for saving and restoring a VM that is in VMX operation. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: -
Paolo Bonzini authored
If the vCPU enters system management mode while running a nested guest, RSM starts processing the vmentry while still in SMM. In that case, however, the pages pointed to by the vmcs12 might be incorrectly loaded from SMRAM. To avoid this, delay the handling of the pages until just before the next vmentry. This is done with a new request and a new entry in kvm_x86_ops, which we will be able to reuse for nested VMX state migration. Extracted from a patch by Jim Mattson and KarimAllah Ahmed. Signed-off-by: -
Paolo Bonzini authored
The test calls KVM_RUN repeatedly, and creates an entirely new VM with the old memory and vCPU state on every exit to userspace. The kvm_util API is expanded with two functions that manage the lifetime of a kvm_vm struct: the first closes the file descriptors and leaves the memory allocated, and the second opens the file descriptors and reuses the memory from the previous incarnation of the kvm_vm struct. For now the test is very basic, as it does not test for example XSAVE or vCPU events. However, it will test nested virtualization state starting with the next patch. Signed-off-by: -
Paolo Bonzini authored
The selftests were not munmap-ing the kvm_run area from the vcpu file descriptor. The result was that kvm_vcpu_release was not called and a reference was left in the parent "struct kvm". Ultimately this was visible in the upcoming state save/restore test as an error when KVM attempted to create a duplicate debugfs entry. Signed-off-by: -
Paolo Bonzini authored
The allocation of the VMXON and VMCS is currently done twice, in lib/vmx.c and in vmx_tsc_adjust_test.c. Reorganize the code to provide a cleaner and easier to use API to the tests. lib/vmx.c now does the complete setup of the VMX data structures, but does not create the VM or set CPUID. This has to be done by the caller. Signed-off-by: -
Paolo Bonzini authored
The GDT and the TSS base were left to zero, and this has interesting effects when the TSS descriptor is later read to set up a VMCS's TR_BASE. Basically it worked by chance, and this patch fixes it by setting up all the protected mode data structures properly. Because the GDT and TSS addresses are virtual, the page tables now always exist at the time of vcpu setup. Signed-off-by: -
Paolo Bonzini authored
Some of the MSRs returned by GET_MSR_INDEX_LIST currently cannot be sent back to KVM_GET_MSR and/or KVM_SET_MSR; either they can never be sent back, or you they are only accepted under special conditions. This makes the API a pain to use. To avoid this pain, this patch makes it so that the result of the get-list ioctl can always be used for host-initiated get and set. Since we don't have a separate way to check for read-only MSRs, this means some Hyper-V MSRs are ignored when written. Arguably they should not even be in the result of GET_MSR_INDEX_LIST, but I am leaving there in case userspace is using the outcome of GET_MSR_INDEX_LIST to derive the support for the corresponding Hyper-V feature. Cc: stable@vger.kernel.org Signed-off-by: -
Sean Christopherson authored
Linux does not support Memory Protection Extensions (MPX) in the kernel itself, thus the BNDCFGS (Bound Config Supervisor) MSR will always be zero in the KVM host, i.e. RDMSR in vmx_save_host_state() is superfluous. KVM unconditionally sets VM_EXIT_CLEAR_BNDCFGS, i.e. BNDCFGS will always be zero after VMEXIT, thus manually loading BNDCFGS is also superfluous. And in the event the MPX kernel support is added (unlikely given that MPX for userspace is in its death throes[1]), BNDCFGS will likely be common across all CPUs[2], and at the least shouldn't change on a regular basis, i.e. saving the MSR on every VMENTRY is completely unnecessary. WARN_ONCE in hardware_setup() if the host's BNDCFGS is non-zero to document that KVM does not preserve BNDCFGS and to serve as a hint as to how BNDCFGS likely should be handled if MPX is used in the kernel, e.g. BNDCFGS should be saved once during KVM setup. [1] https://lkml.org/lkml/2018/4/27/1046 [2] http://www.openwall.com/lists/kernel-hardening/2017/07/24/28 Signed-off-by:
Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:
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KarimAllah Ahmed authored
Switch 'requests' to be explicitly 64-bit and update BUILD_BUG_ON check to use the size of "requests" instead of the hard-coded '32'. That gives us a bit more room again for arch-specific requests as we already ran out of space for x86 due to the hard-coded check. The only exception here is ARM32 as it is still 32-bits. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim KrÄmář <rkrcmar@redhat.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by:
KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by:
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Wei Huang authored
KVM is supposed to update some guest VM's CPUID bits (e.g. OSXSAVE) when CR4 is changed. A bug was found in KVM recently and it was fixed by Commit c4d21882 ("KVM: x86: Update cpuid properly when CR4.OSXAVE or CR4.PKE is changed"). This patch adds a test to verify the synchronization between guest VM's CR4 and CPUID bits. Signed-off-by:
Wei Huang <wei@redhat.com> Signed-off-by:
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Paolo Bonzini authored
Pull bug fixes into the KVM development tree to avoid nasty conflicts.
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- Aug 02, 2018
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Paolo Bonzini authored
Merge tag 'kvm-s390-next-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Features for 4.19 - initial version for host large page support. Must be enabled with module parameter hpage=1 and will conflict with the nested=1 parameter. - enable etoken facility for guests - Fixes
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Paolo Bonzini authored
Merge tag 'kvm-ppc-next-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD PPC KVM update for 4.19. This update adds no new features; it just has some minor code cleanups and bug fixes, including a fix to allow us to create KVM_MAX_VCPUS vCPUs on POWER9 in all CPU threading modes.
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- Jul 31, 2018
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Janosch Frank authored
Merge tag 'hlp_stage1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvms390/next KVM: s390: initial host large page support - must be enabled via module parameter hpage=1 - cannot be used together with nested - does support migration - does support hugetlbfs - no THP yet
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Janosch Frank authored
General KVM huge page support on s390 has to be enabled via the kvm.hpage module parameter. Either nested or hpage can be enabled, as we currently do not support vSIE for huge backed guests. Once the vSIE support is added we will either drop the parameter or enable it as default. For a guest the feature has to be enabled through the new KVM_CAP_S390_HPAGE_1M capability and the hpage module parameter. Enabling it means that cmm can't be enabled for the vm and disables pfmf and storage key interpretation. This is due to the fact that in some cases, in upcoming patches, we have to split huge pages in the guest mapping to be able to set more granular memory protection on 4k pages. These split pages have fake page tables that are not visible to the Linux memory management which subsequently will not manage its PGSTEs, while the SIE will. Disabling these features lets us manage PGSTE data in a consistent matter and solve that problem. Signed-off-by:
Janosch Frank <frankja@linux.ibm.com> Reviewed-by:
David Hildenbrand <david@redhat.com>
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Janosch Frank authored
Let's allow huge pmd linking when enabled through the KVM_CAP_S390_HPAGE_1M capability. Also we can now restrict gmap invalidation and notification to the cases where the capability has been activated and save some cycles when that's not the case. Signed-off-by:
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Dominik Dingel authored
Guests backed by huge pages could theoretically free unused pages via the diagnose 10 instruction. We currently don't allow that, so we don't have to refault it once it's needed again. Signed-off-by:
Dominik Dingel <dingel@linux.vnet.ibm.com> Reviewed-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Reviewed-by:
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- Jul 30, 2018
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Janosch Frank authored
Let's introduce an explicit check if skeys have already been enabled for the vcpu, so we don't have to check the mm context if we don't have the storage key facility. This lets us check for enablement without having to take the mm semaphore and thus speedup skey emulation. Signed-off-by:
Farhan Ali <alifm@linux.ibm.com> Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com>
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Janosch Frank authored
When doing skey emulation for huge guests, we now need to fault in pmds, as we don't have PGSTES anymore to store them when we do not have valid table entries. Signed-off-by: -
Janosch Frank authored
Storage keys for guests with huge page mappings have to be managed in hardware. There are no PGSTEs for PMDs that we could use to retain the guests's logical view of the key. Signed-off-by:
Janosch Frank <frankja@linux.vnet.ibm.com> Reviewed-by:
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