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2020-02-12KVM: x86/mmu: Avoid retpoline on ->page_fault() with TDPSean Christopherson
Wrap calls to ->page_fault() with a small shim to directly invoke the TDP fault handler when the kernel is using retpolines and TDP is being used. Single out the TDP fault handler and annotate the TDP path as likely to coerce the compiler into preferring it over the indirect function call. Rename tdp_page_fault() to kvm_tdp_page_fault(), as it's exposed outside of mmu.c to allow inlining the shim. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-04kvm: x86: mmu: Recovery of shattered NX large pagesJunaid Shahid
The page table pages corresponding to broken down large pages are zapped in FIFO order, so that the large page can potentially be recovered, if it is not longer being used for execution. This removes the performance penalty for walking deeper EPT page tables. By default, one large page will last about one hour once the guest reaches a steady state. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2019-08-22KVM: x86/mmu: Add explicit access mask for MMIO SPTEsSean Christopherson
When shadow paging is enabled, KVM tracks the allowed access type for MMIO SPTEs so that it can do a permission check on a MMIO GVA cache hit without having to walk the guest's page tables. The tracking is done by retaining the WRITE and USER bits of the access when inserting the MMIO SPTE (read access is implicitly allowed), which allows the MMIO page fault handler to retrieve and cache the WRITE/USER bits from the SPTE. Unfortunately for EPT, the mask used to retain the WRITE/USER bits is hardcoded using the x86 paging versions of the bits. This funkiness happens to work because KVM uses a completely different mask/value for MMIO SPTEs when EPT is enabled, and the EPT mask/value just happens to overlap exactly with the x86 WRITE/USER bits[*]. Explicitly define the access mask for MMIO SPTEs to accurately reflect that EPT does not want to incorporate any access bits into the SPTE, and so that KVM isn't subtly relying on EPT's WX bits always being set in MMIO SPTEs, e.g. attempting to use other bits for experimentation breaks horribly. Note, vcpu_match_mmio_gva() explicits prevents matching GVA==0, and all TDP flows explicit set mmio_gva to 0, i.e. zeroing vcpu->arch.access for EPT has no (known) functional impact. [*] Using WX to generate EPT misconfigurations (equivalent to reserved bit page fault) ensures KVM can employ its MMIO page fault tricks even platforms without reserved address bits. Fixes: ce88decffd17 ("KVM: MMU: mmio page fault support") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-04-16kvm: mmu: Fix overflow on kvm mmu page limit calculationBen Gardon
KVM bases its memory usage limits on the total number of guest pages across all memslots. However, those limits, and the calculations to produce them, use 32 bit unsigned integers. This can result in overflow if a VM has more guest pages that can be represented by a u32. As a result of this overflow, KVM can use a low limit on the number of MMU pages it will allocate. This makes KVM unable to map all of guest memory at once, prompting spurious faults. Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch introduced no new failures. Signed-off-by: Ben Gardon <bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-02-20Revert "KVM: MMU: fast invalidate all pages"Sean Christopherson
Remove x86 KVM's fast invalidate mechanism, i.e. revert all patches from the original series[1], now that all users of the fast invalidate mechanism are gone. This reverts commit 5304b8d37c2a5ebca48330f5e7868d240eafbed1. [1] https://lkml.kernel.org/r/1369960590-14138-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com Cc: Xiao Guangrong <guangrong.xiao@gmail.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-10-17x86/kvm/mmu: make vcpu->mmu a pointer to the current MMUVitaly Kuznetsov
As a preparation to full MMU split between L1 and L2 make vcpu->arch.mmu a pointer to the currently used mmu. For now, this is always vcpu->arch.root_mmu. No functional change. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
2018-10-17KVM: x86: move definition PT_MAX_HUGEPAGE_LEVEL and KVM_NR_PAGE_SIZES togetherWei Yang
Currently, there are two definitions related to huge page, but a little bit far from each other and seems loosely connected: * KVM_NR_PAGE_SIZES defines the number of different size a page could map * PT_MAX_HUGEPAGE_LEVEL means the maximum level of huge page The number of different size a page could map equals the maximum level of huge page, which is implied by current definition. While current implementation may not be kind to readers and further developers: * KVM_NR_PAGE_SIZES looks like a stand alone definition at first sight * in case we need to support more level, two places need to change This patch tries to make these two definition more close, so that reader and developer would feel more comfortable to manipulate. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Propagate guest PCIDs to host PCIDsJunaid Shahid
When using shadow paging mode, propagate the guest's PCID value to the shadow CR3 in the host instead of always using PCID 0. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Add ability to skip TLB flush when switching CR3Junaid Shahid
Remove the implicit flush from the set_cr3 handlers, so that the callers are able to decide whether to flush the TLB or not. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Use fast CR3 switch for nested VMXJunaid Shahid
Use the fast CR3 switch mechanism to locklessly change the MMU root page when switching between L1 and L2. The switch from L2 to L1 should always go through the fast path, while the switch from L1 to L2 should go through the fast path if L1's CR3/EPTP for L2 hasn't changed since the last time. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Support resetting the MMU context without resetting rootsJunaid Shahid
This adds support for re-initializing the MMU context in a different mode while preserving the active root_hpa and the prev_root. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Introduce KVM_REQ_LOAD_CR3Junaid Shahid
The KVM_REQ_LOAD_CR3 request loads the hardware CR3 using the current root_hpa. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-11-16Merge tag 'kvm-4.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Radim Krčmář: "First batch of KVM changes for 4.15 Common: - Python 3 support in kvm_stat - Accounting of slabs to kmemcg ARM: - Optimized arch timer handling for KVM/ARM - Improvements to the VGIC ITS code and introduction of an ITS reset ioctl - Unification of the 32-bit fault injection logic - More exact external abort matching logic PPC: - Support for running hashed page table (HPT) MMU mode on a host that is using the radix MMU mode; single threaded mode on POWER 9 is added as a pre-requisite - Resolution of merge conflicts with the last second 4.14 HPT fixes - Fixes and cleanups s390: - Some initial preparation patches for exitless interrupts and crypto - New capability for AIS migration - Fixes x86: - Improved emulation of LAPIC timer mode changes, MCi_STATUS MSRs, and after-reset state - Refined dependencies for VMX features - Fixes for nested SMI injection - A lot of cleanups" * tag 'kvm-4.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (89 commits) KVM: s390: provide a capability for AIS state migration KVM: s390: clear_io_irq() requests are not expected for adapter interrupts KVM: s390: abstract conversion between isc and enum irq_types KVM: s390: vsie: use common code functions for pinning KVM: s390: SIE considerations for AP Queue virtualization KVM: s390: document memory ordering for kvm_s390_vcpu_wakeup KVM: PPC: Book3S HV: Cosmetic post-merge cleanups KVM: arm/arm64: fix the incompatible matching for external abort KVM: arm/arm64: Unify 32bit fault injection KVM: arm/arm64: vgic-its: Implement KVM_DEV_ARM_ITS_CTRL_RESET KVM: arm/arm64: Document KVM_DEV_ARM_ITS_CTRL_RESET KVM: arm/arm64: vgic-its: Free caches when GITS_BASER Valid bit is cleared KVM: arm/arm64: vgic-its: New helper functions to free the caches KVM: arm/arm64: vgic-its: Remove kvm_its_unmap_device arm/arm64: KVM: Load the timer state when enabling the timer KVM: arm/arm64: Rework kvm_timer_should_fire KVM: arm/arm64: Get rid of kvm_timer_flush_hwstate KVM: arm/arm64: Avoid phys timer emulation in vcpu entry/exit KVM: arm/arm64: Move phys_timer_emulate function KVM: arm/arm64: Use kvm_arm_timer_set/get_reg for guest register traps ...
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-12KVM: SVM: limit kvm_handle_page_fault to #PF handlingPaolo Bonzini
It has always annoyed me a bit how SVM_EXIT_NPF is handled by pf_interception. This is also the only reason behind the under-documented need_unprotect argument to kvm_handle_page_fault. Let NPF go straight to kvm_mmu_page_fault, just like VMX does in handle_ept_violation and handle_ept_misconfig. Reviewed-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-08Merge branch 'kvm-ppc-fixes' of ↵Radim Krčmář
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc This fix was intended for 4.13, but didn't get in because both maintainers were on vacation. Paul Mackerras: "It adds mutual exclusion between list_add_rcu and list_del_rcu calls on the kvm->arch.spapr_tce_tables list. Without this, userspace could potentially trigger corruption of the list and cause a host crash or worse."
2017-08-25KVM: x86: simplify handling of PKRUPaolo Bonzini
Move it to struct kvm_arch_vcpu, replacing guest_pkru_valid with a simple comparison against the host value of the register. The write of PKRU in addition can be skipped if the guest has not enabled the feature. Once we do this, we need not test OSPKE in the host anymore, because guest_CR4.PKE=1 implies host_CR4.PKE=1. The static PKU test is kept to elide the code on older CPUs. Suggested-by: Yang Zhang <zy107165@alibaba-inc.com> Fixes: 1be0e61c1f255faaeab04a390e00c8b9b9042870 Cc: stable@vger.kernel.org Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-24KVM: MMU: Add 5 level EPT & Shadow page table support.Yu Zhang
Extends the shadow paging code, so that 5 level shadow page table can be constructed if VM is running in 5 level paging mode. Also extends the ept code, so that 5 level ept table can be constructed if maxphysaddr of VM exceeds 48 bits. Unlike the shadow logic, KVM should still use 4 level ept table for a VM whose physical address width is less than 48 bits, even when the VM is running in 5 level paging mode. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> [Unconditionally reset the MMU context in kvm_cpuid_update. Changing MAXPHYADDR invalidates the reserved bit bitmasks. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-24KVM: MMU: Rename PT64_ROOT_LEVEL to PT64_ROOT_4LEVEL.Yu Zhang
Now we have 4 level page table and 5 level page table in 64 bits long mode, let's rename the PT64_ROOT_LEVEL to PT64_ROOT_4LEVEL, then we can use PT64_ROOT_5LEVEL for 5 level page table, it's helpful to make the code more clear. Also PT64_ROOT_MAX_LEVEL is defined as 4, so that we can just redefine it to 5 whenever a replacement is needed for 5 level paging. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-24KVM: MMU: check guest CR3 reserved bits based on its physical address width.Yu Zhang
Currently, KVM uses CR3_L_MODE_RESERVED_BITS to check the reserved bits in CR3. Yet the length of reserved bits in guest CR3 should be based on the physical address width exposed to the VM. This patch changes CR3 check logic to calculate the reserved bits at runtime. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-18KVM: x86: simplify ept_misconfigPaolo Bonzini
Calling handle_mmio_page_fault() has been unnecessary since commit e9ee956e311d ("KVM: x86: MMU: Move handle_mmio_page_fault() call to kvm_mmu_page_fault()", 2016-02-22). handle_mmio_page_fault() can now be made static. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-07-14KVM: async_pf: Add L1 guest async_pf #PF vmexit handlerWanpeng Li
This patch adds the L1 guest async page fault #PF vmexit handler, such by L1 similar to ordinary async page fault. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> [Passed insn parameters to kvm_mmu_page_fault().] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-07-06Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Paolo Bonzini: "PPC: - Better machine check handling for HV KVM - Ability to support guests with threads=2, 4 or 8 on POWER9 - Fix for a race that could cause delayed recognition of signals - Fix for a bug where POWER9 guests could sleep with interrupts pending. ARM: - VCPU request overhaul - allow timer and PMU to have their interrupt number selected from userspace - workaround for Cavium erratum 30115 - handling of memory poisonning - the usual crop of fixes and cleanups s390: - initial machine check forwarding - migration support for the CMMA page hinting information - cleanups and fixes x86: - nested VMX bugfixes and improvements - more reliable NMI window detection on AMD - APIC timer optimizations Generic: - VCPU request overhaul + documentation of common code patterns - kvm_stat improvements" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (124 commits) Update my email address kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS x86: kvm: mmu: use ept a/d in vmcs02 iff used in vmcs12 kvm: x86: mmu: allow A/D bits to be disabled in an mmu x86: kvm: mmu: make spte mmio mask more explicit x86: kvm: mmu: dead code thanks to access tracking KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code KVM: PPC: Book3S HV: Close race with testing for signals on guest entry KVM: PPC: Book3S HV: Simplify dynamic micro-threading code KVM: x86: remove ignored type attribute KVM: LAPIC: Fix lapic timer injection delay KVM: lapic: reorganize restart_apic_timer KVM: lapic: reorganize start_hv_timer kvm: nVMX: Check memory operand to INVVPID KVM: s390: Inject machine check into the nested guest KVM: s390: Inject machine check into the guest tools/kvm_stat: add new interactive command 'b' tools/kvm_stat: add new command line switch '-i' tools/kvm_stat: fix error on interactive command 'g' KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit ...
2017-07-03x86: kvm: mmu: make spte mmio mask more explicitPeter Feiner
Specify both a mask (i.e., bits to consider) and a value (i.e., pattern of bits that indicates a special PTE) for mmio SPTEs. On Intel, this lets us pack even more information into the (SPTE_SPECIAL_MASK | EPT_VMX_RWX_MASK) mask we use for access tracking liberating all (SPTE_SPECIAL_MASK | (non-misconfigured-RWX)) values. Signed-off-by: Peter Feiner <pfeiner@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-06-11KVM: async_pf: avoid async pf injection when in guest modeWanpeng Li
INFO: task gnome-terminal-:1734 blocked for more than 120 seconds. Not tainted 4.12.0-rc4+ #8 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. gnome-terminal- D 0 1734 1015 0x00000000 Call Trace: __schedule+0x3cd/0xb30 schedule+0x40/0x90 kvm_async_pf_task_wait+0x1cc/0x270 ? __vfs_read+0x37/0x150 ? prepare_to_swait+0x22/0x70 do_async_page_fault+0x77/0xb0 ? do_async_page_fault+0x77/0xb0 async_page_fault+0x28/0x30 This is triggered by running both win7 and win2016 on L1 KVM simultaneously, and then gives stress to memory on L1, I can observed this hang on L1 when at least ~70% swap area is occupied on L0. This is due to async pf was injected to L2 which should be injected to L1, L2 guest starts receiving pagefault w/ bogus %cr2(apf token from the host actually), and L1 guest starts accumulating tasks stuck in D state in kvm_async_pf_task_wait() since missing PAGE_READY async_pfs. This patch fixes the hang by doing async pf when executing L1 guest. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-05-09kvm: x86: Add a hook for arch specific dirty logging emulationBandan Das
When KVM updates accessed/dirty bits, this hook can be used to invoke an arch specific function that implements/emulates dirty logging such as PML. Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-07kvm: nVMX: support EPT accessed/dirty bitsPaolo Bonzini
Now use bit 6 of EPTP to optionally enable A/D bits for EPTP. Another thing to change is that, when EPT accessed and dirty bits are not in use, VMX treats accesses to guest paging structures as data reads. When they are in use (bit 6 of EPTP is set), they are treated as writes and the corresponding EPT dirty bit is set. The MMU didn't know this detail, so this patch adds it. We also have to fix up the exit qualification. It may be wrong because KVM sets bit 6 but the guest might not. L1 emulates EPT A/D bits using write permissions, so in principle it may be possible for EPT A/D bits to be used by L1 even though not available in hardware. The problem is that guest page-table walks will be treated as reads rather than writes, so they would not cause an EPT violation. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Fixed typo in walk_addr_generic() comment and changed bit clear + conditional-set pattern in handle_ept_violation() to conditional-clear] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-07-14kvm: mmu: remove is_present_gpte()Bandan Das
We have two versions of the above function. To prevent confusion and bugs in the future, remove the non-FNAME version entirely and replace all calls with the actual check. Signed-off-by: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-04-10KVM: MMU: fix permission_fault()Xiao Guangrong
kvm-unit-tests complained about the PFEC is not set properly, e.g,: test pte.rw pte.d pte.nx pde.p pde.rw pde.pse user fetch: FAIL: error code 15 expected 5 Dump mapping: address: 0x123400000000 ------L4: 3e95007 ------L3: 3e96007 ------L2: 2000083 It's caused by the reason that PFEC returned to guest is copied from the PFEC triggered by shadow page table This patch fixes it and makes the logic of updating errcode more clean Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Do not assume pfec.p=1. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22KVM, pkeys: add pkeys support for permission_faultHuaitong Han
Protection keys define a new 4-bit protection key field (PKEY) in bits 62:59 of leaf entries of the page tables, the PKEY is an index to PKRU register(16 domains), every domain has 2 bits(write disable bit, access disable bit). Static logic has been produced in update_pkru_bitmask, dynamic logic need read pkey from page table entries, get pkru value, and deduce the correct result. [ Huaitong: Xiao helps to modify many sections. ] Signed-off-by: Huaitong Han <huaitong.han@intel.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22KVM: MMU: return page fault error code from permission_faultPaolo Bonzini
This will help in the implementation of PKRU, where the PK bit of the page fault error code cannot be computed in advance (unlike I/D, R/W and U/S). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: introduce kvm_mmu_slot_gfn_write_protectXiao Guangrong
Split rmap_write_protect() and introduce the function to abstract the write protection based on the slot This function will be used in the later patch Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: introduce kvm_mmu_gfn_{allow,disallow}_lpageXiao Guangrong
Abstract the common operations from account_shadowed() and unaccount_shadowed(), then introduce kvm_mmu_gfn_disallow_lpage() and kvm_mmu_gfn_allow_lpage() These two functions will be used by page tracking in the later patch Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-10KVM: x86: merge handle_mmio_page_fault and handle_mmio_page_fault_commonPaolo Bonzini
They are exactly the same, except that handle_mmio_page_fault has an unused argument and a call to WARN_ON. Remove the unused argument from the callers, and move the warning to (the former) handle_mmio_page_fault_common. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-08-05KVM: VMX: drop ept misconfig checkXiao Guangrong
The logic used to check ept misconfig is completely contained in common reserved bits check for sptes, so it can be removed Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-08-05KVM: MMU: introduce the framework to check zero bits on sptesXiao Guangrong
We have abstracted the data struct and functions which are used to check reserved bit on guest page tables, now we extend the logic to check zero bits on shadow page tables The zero bits on sptes include not only reserved bits on hardware but also the bits that SPTEs willnever use. For example, shadow pages will never use GB pages unless the guest uses them too. Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-19KVM: MMU: fix MTRR updateXiao Guangrong
Currently, whenever guest MTRR registers are changed kvm_mmu_reset_context is called to switch to the new root shadow page table, however, it's useless since: 1) the cache type is not cached into shadow page's attribute so that the original root shadow page will be reused 2) the cache type is set on the last spte, that means we should sync the last sptes when MTRR is changed This patch fixs this issue by drop all the spte in the gfn range which is being updated by MTRR Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-19KVM: MMU: introduce PT_MAX_HUGEPAGE_LEVELXiao Guangrong
Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-19KVM: MMU: fix SMAP virtualizationXiao Guangrong
KVM may turn a user page to a kernel page when kernel writes a readonly user page if CR0.WP = 1. This shadow page entry will be reused after SMAP is enabled so that kernel is allowed to access this user page Fix it by setting SMAP && !CR0.WP into shadow page's role and reset mmu once CR4.SMAP is updated Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-05-08KVM: MMU: fix smap permission checkXiao Guangrong
Current permission check assumes that RSVD bit in PFEC is always zero, however, it is not true since MMIO #PF will use it to quickly identify MMIO access Fix it by clearing the bit if walking guest page table is needed Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-09KVM: x86: #PF error-code on R/W operations is wrongNadav Amit
When emulating an instruction that reads the destination memory operand (i.e., instructions without the Mov flag in the emulator), the operand is first read. If a page-fault is detected in this phase, the error-code which would be delivered to the VM does not indicate that the access that caused the exception is a write one. This does not conform with real hardware, and may cause the VM to enter the page-fault handler twice for no reason (once for read, once for write). Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-01-08KVM: x86: mmu: remove argument to kvm_init_shadow_mmu and ↵Paolo Bonzini
kvm_init_shadow_ept_mmu The initialization function in mmu.c can always use walk_mmu, which is known to be vcpu->arch.mmu. Only init_kvm_nested_mmu is used to initialize vcpu->arch.nested_mmu. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03KVM: mmio: cleanup kvm_set_mmio_spte_maskTiejun Chen
Just reuse rsvd_bits() inside kvm_set_mmio_spte_mask() for slightly better code. Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-04-23KVM: MMU: flush tlb out of mmu lock when write-protect the sptesXiao Guangrong
Now we can flush all the TLBs out of the mmu lock without TLB corruption when write-proect the sptes, it is because: - we have marked large sptes readonly instead of dropping them that means we just change the spte from writable to readonly so that we only need to care the case of changing spte from present to present (changing the spte from present to nonpresent will flush all the TLBs immediately), in other words, the only case we need to care is mmu_spte_update() - in mmu_spte_update(), we haved checked SPTE_HOST_WRITEABLE | PTE_MMU_WRITEABLE instead of PT_WRITABLE_MASK, that means it does not depend on PT_WRITABLE_MASK anymore Acked-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2014-04-14KVM: Add SMAP support when setting CR4Feng Wu
This patch adds SMAP handling logic when setting CR4 for guests Thanks a lot to Paolo Bonzini for his suggestion to use the branchless way to detect SMAP violation. Signed-off-by: Feng Wu <feng.wu@intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-10-03KVM: mmu: change useless int return types to voidPaolo Bonzini
kvm_mmu initialization is mostly filling in function pointers, there is no way for it to fail. Clean up unused return values. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-08-07nEPT: MMU context for nested EPTNadav Har'El
KVM's existing shadow MMU code already supports nested TDP. To use it, we need to set up a new "MMU context" for nested EPT, and create a few callbacks for it (nested_ept_*()). This context should also use the EPT versions of the page table access functions (defined in the previous patch). Then, we need to switch back and forth between this nested context and the regular MMU context when switching between L1 and L2 (when L1 runs this L2 with EPT). Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Signed-off-by: Nadav Har'El <nyh@il.ibm.com> Signed-off-by: Jun Nakajima <jun.nakajima@intel.com> Signed-off-by: Xinhao Xu <xinhao.xu@intel.com> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27KVM: MMU: fast invalidate all mmio sptesXiao Guangrong
This patch tries to introduce a very simple and scale way to invalidate all mmio sptes - it need not walk any shadow pages and hold mmu-lock KVM maintains a global mmio valid generation-number which is stored in kvm->memslots.generation and every mmio spte stores the current global generation-number into his available bits when it is created When KVM need zap all mmio sptes, it just simply increase the global generation-number. When guests do mmio access, KVM intercepts a MMIO #PF then it walks the shadow page table and get the mmio spte. If the generation-number on the spte does not equal the global generation-number, it will go to the normal #PF handler to update the mmio spte Since 19 bits are used to store generation-number on mmio spte, we zap all mmio sptes when the number is round Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Gleb Natapov <gleb@redhat.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-27KVM: MMU: make return value of mmio page fault handler more readableXiao Guangrong
Define some meaningful names instead of raw code Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Gleb Natapov <gleb@redhat.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-06-05KVM: MMU: fast invalidate all pagesXiao Guangrong
The current kvm_mmu_zap_all is really slow - it is holding mmu-lock to walk and zap all shadow pages one by one, also it need to zap all guest page's rmap and all shadow page's parent spte list. Particularly, things become worse if guest uses more memory or vcpus. It is not good for scalability In this patch, we introduce a faster way to invalidate all shadow pages. KVM maintains a global mmu invalid generation-number which is stored in kvm->arch.mmu_valid_gen and every shadow page stores the current global generation-number into sp->mmu_valid_gen when it is created When KVM need zap all shadow pages sptes, it just simply increase the global generation-number then reload root shadow pages on all vcpus. Vcpu will create a new shadow page table according to current kvm's generation-number. It ensures the old pages are not used any more. Then the obsolete pages (sp->mmu_valid_gen != kvm->arch.mmu_valid_gen) are zapped by using lock-break technique Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>