- 09 5月, 2017 1 次提交
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由 Bandan Das 提交于
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: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 07 4月, 2017 1 次提交
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由 Paolo Bonzini 提交于
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: NPaolo 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: NRadim Krčmář <rkrcmar@redhat.com>
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- 02 3月, 2017 1 次提交
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由 Ingo Molnar 提交于
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 28 2月, 2017 1 次提交
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由 Masahiro Yamada 提交于
Fix typos and add the following to the scripts/spelling.txt: an user||a user an userspace||a userspace I also added "userspace" to the list since it is a common word in Linux. I found some instances for "an userfaultfd", but I did not add it to the list. I felt it is endless to find words that start with "user" such as "userland" etc., so must draw a line somewhere. Link: http://lkml.kernel.org/r/1481573103-11329-4-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 1月, 2017 4 次提交
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由 Junaid Shahid 提交于
Before fast page fault restores an access track PTE back to a regular PTE, it now also verifies that the restored PTE would grant the necessary permissions for the faulting access to succeed. If not, it falls back to the slow page fault path. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
Redo the page table walk in fast_page_fault when retrying so that we are working on the latest PTE even if the hierarchy changes. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
Reword the comment to hopefully make it more clear. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
Instead of the caller including the SPTE_SPECIAL_MASK in the masks being supplied to kvm_mmu_set_mmio_spte_mask() and kvm_mmu_set_mask_ptes(), those functions now themselves include the SPTE_SPECIAL_MASK. Note that bit 63 is now reset in the default MMIO mask. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 09 1月, 2017 7 次提交
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由 Junaid Shahid 提交于
This change implements lockless access tracking for Intel CPUs without EPT A bits. This is achieved by marking the PTEs as not-present (but not completely clearing them) when clear_flush_young() is called after marking the pages as accessed. When an EPT Violation is generated as a result of the VM accessing those pages, the PTEs are restored to their original values. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
mmu_spte_update() tracks changes in the accessed/dirty state of the SPTE being updated and calls kvm_set_pfn_accessed/dirty appropriately. However, in some cases (e.g. when aging the SPTE), this shouldn't be done. mmu_spte_update_no_track() is introduced for use in such cases. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
This simplifies mmu_spte_update() a little bit. The checks for clearing of accessed and dirty bits are refactored into separate functions, which are used inside both mmu_spte_update() and mmu_spte_clear_track_bits(), as well as kvm_test_age_rmapp(). The new helper functions handle both the case when A/D bits are supported in hardware and the case when they are not. Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
This change adds retries into the Fast Page Fault path. Without the retries, the code still works, but if a retry does end up being needed, then it will result in a second page fault for the same memory access, which will cause much more overhead compared to just retrying within the original fault. This would be especially useful with the upcoming fast access tracking change, as that would make it more likely for retries to be needed (e.g. due to read and write faults happening on different CPUs at the same time). Signed-off-by: NJunaid Shahid <junaids@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Junaid Shahid 提交于
This change renames spte_is_locklessly_modifiable() to spte_can_locklessly_be_made_writable() to distinguish it from other forms of lockless modifications. The full set of lockless modifications is covered by spte_has_volatile_bits(). Signed-off-by: NJunaid Shahid <junaids@google.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 David Matlack 提交于
When using two-dimensional paging, the mmu_page_hash (which provides lookups for existing kvm_mmu_page structs), becomes imbalanced; with too many collisions in buckets 0 and 512. This has been seen to cause mmu_lock to be held for multiple milliseconds in kvm_mmu_get_page on VMs with a large amount of RAM mapped with 4K pages. The current hash function uses the lower 10 bits of gfn to index into mmu_page_hash. When doing shadow paging, gfn is the address of the guest page table being shadow. These tables are 4K-aligned, which makes the low bits of gfn a good hash. However, with two-dimensional paging, no guest page tables are being shadowed, so gfn is the base address that is mapped by the table. Thus page tables (level=1) have a 2MB aligned gfn, page directories (level=2) have a 1GB aligned gfn, etc. This means hashes will only differ in their 10th bit. hash_64() provides a better hash. For example, on a VM with ~200G (99458 direct=1 kvm_mmu_page structs): hash max_mmu_page_hash_collisions -------------------------------------------- low 10 bits 49847 hash_64 105 perfect 97 While we're changing the hash, increase the table size by 4x to better support large VMs (further reduces number of collisions in 200G VM to 29). Note that hash_64() does not provide a good distribution prior to commit ef703f49 ("Eliminate bad hash multipliers from hash_32() and hash_64()"). Signed-off-by: NDavid Matlack <dmatlack@google.com> Change-Id: I5aa6b13c834722813c6cca46b8b1ed6f53368ade Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 David Matlack 提交于
Report the maximum number of mmu_page_hash collisions as a per-VM stat. This will make it easy to identify problems with the mmu_page_hash in the future. Signed-off-by: NDavid Matlack <dmatlack@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 25 11月, 2016 1 次提交
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由 Tom Lendacky 提交于
AMD hardware adds two additional bits to aid in nested page fault handling. Bit 32 - NPF occurred while translating the guest's final physical address Bit 33 - NPF occurred while translating the guest page tables The guest page tables fault indicator can be used as an aid for nested virtualization. Using V0 for the host, V1 for the first level guest and V2 for the second level guest, when both V1 and V2 are using nested paging there are currently a number of unnecessary instruction emulations. When V2 is launched shadow paging is used in V1 for the nested tables of V2. As a result, KVM marks these pages as RO in the host nested page tables. When V2 exits and we resume V1, these pages are still marked RO. Every nested walk for a guest page table is treated as a user-level write access and this causes a lot of NPFs because the V1 page tables are marked RO in the V0 nested tables. While executing V1, when these NPFs occur KVM sees a write to a read-only page, emulates the V1 instruction and unprotects the page (marking it RW). This patch looks for cases where we get a NPF due to a guest page table walk where the page was marked RO. It immediately unprotects the page and resumes the guest, leading to far fewer instruction emulations when nested virtualization is used. Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com> Reviewed-by: NBorislav Petkov <bp@suse.de> Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 23 11月, 2016 1 次提交
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由 Bandan Das 提交于
Change unimplemented msrs messages to use pr_debug. If CONFIG_DYNAMIC_DEBUG is set, then these messages can be enabled at run time or else -DDEBUG can be used at compile time to enable them. These messages will still be printed if ignore_msrs=1. Signed-off-by: NBandan Das <bsd@redhat.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 04 11月, 2016 2 次提交
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由 Jike Song 提交于
The user of page_track might needs extra information, so pass the kvm_page_track_notifier_node to callbacks. Signed-off-by: NJike Song <jike.song@intel.com> Reviewed-by: NXiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Xiaoguang Chen 提交于
When a memory slot is being moved or removed users of page track can be notified. So users can drop write-protection for the pages in that memory slot. This notifier type is needed by KVMGT to sync up its shadow page table when memory slot is being moved or removed. Register the notifier type track_flush_slot to receive memslot move and remove event. Reviewed-by: NXiao Guangrong <guangrong.xiao@intel.com> Signed-off-by: NChen Xiaoguang <xiaoguang.chen@intel.com> [Squashed commits to avoid bisection breakage and reworded the subject.] Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 03 11月, 2016 2 次提交
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由 Xiaoguang Chen 提交于
When a memory slot is being moved or removed users of page track can be notified. So users can drop write-protection for the pages in that memory slot. This notifier type is needed by KVMGT to sync up its shadow page table when memory slot is being moved or removed. Register the notifier type track_flush_slot to receive memslot move and remove event. Reviewed-by: NXiao Guangrong <guangrong.xiao@intel.com> Signed-off-by: NChen Xiaoguang <xiaoguang.chen@intel.com> [Squashed commits to avoid bisection breakage and reworded the subject.] Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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由 Peter Feiner 提交于
The MMU notifier sequence number keeps GPA->HPA mappings in sync when GPA->HPA lookups are done outside of the MMU lock (e.g., in tdp_page_fault). Since kvm_age_hva doesn't change GPA->HPA, it's unnecessary to increment the sequence number. Signed-off-by: NPeter Feiner <pfeiner@google.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 19 8月, 2016 1 次提交
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由 Bandan Das 提交于
That parameter isn't used in these functions, it's probably a historical artifact. Signed-off-by: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 14 7月, 2016 5 次提交
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由 Paul Gortmaker 提交于
Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. In the case of kvm where it is modular, we can extend that to also include files that are building basic support functionality but not related to loading or registering the final module; such files also have no need whatsoever for module.h The advantage in removing such instances is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each instance for the presence of either and replace as needed. Several instances got replaced with moduleparam.h since that was really all that was required for those particular files. Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com> Acked-by: NPaolo Bonzini <pbonzini@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kvm@vger.kernel.org Link: http://lkml.kernel.org/r/20160714001901.31603-8-paul.gortmaker@windriver.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Bandan Das 提交于
To support execute only mappings on behalf of L1 hypervisors, reuse ACC_USER_MASK to signify if the L1 hypervisor has the R bit set. For the nested EPT case, we assumed that the U bit was always set since there was no equivalent in EPT page tables. Strictly speaking, this was not necessary because handle_ept_violation never set PFERR_USER_MASK in the error code (uf=0 in the parlance of update_permission_bitmask). We now have to set both U and UF correctly, respectively in FNAME(gpte_access) and in handle_ept_violation. Also in handle_ept_violation bit 3 of the exit qualification is not enough to detect a present PTE; all three bits 3-5 have to be checked. Signed-off-by: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Bandan Das 提交于
To support execute only mappings on behalf of L1 hypervisors, we need to teach set_spte() to honor all three of L1's XWR bits. As a start, add a new variable "shadow_present_mask" that will be set for non-EPT shadow paging and clear for EPT. Signed-off-by: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Bandan Das 提交于
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: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Bandan Das 提交于
This is safe because this function is called on host controlled page table and non-present/non-MMIO sptes never use bits 1..31. For the EPT case, this ensures that cases where only the execute bit is set is marked valid. Signed-off-by: NBandan Das <bsd@redhat.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 14 6月, 2016 1 次提交
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由 Andrea Gelmini 提交于
Signed-off-by: NAndrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 02 6月, 2016 1 次提交
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由 Nadav Amit 提交于
In theory, nothing prevents the compiler from write-tearing PTEs, or split PTE writes. These partially-modified PTEs can be fetched by other cores and cause mayhem. I have not really encountered such case in real-life, but it does seem possible. For example, the compiler may try to do something creative for kvm_set_pte_rmapp() and perform multiple writes to the PTE. Signed-off-by: NNadav Amit <nadav.amit@gmail.com> Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
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- 06 5月, 2016 1 次提交
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由 Andrea Arcangeli 提交于
After the THP refcounting change, obtaining a compound pages from get_user_pages() no longer allows us to assume the entire compound page is immediately mappable from a secondary MMU. A secondary MMU doesn't want to call get_user_pages() more than once for each compound page, in order to know if it can map the whole compound page. So a secondary MMU needs to know from a single get_user_pages() invocation when it can map immediately the entire compound page to avoid a flood of unnecessary secondary MMU faults and spurious atomic_inc()/atomic_dec() (pages don't have to be pinned by MMU notifier users). Ideally instead of the page->_mapcount < 1 check, get_user_pages() should return the granularity of the "page" mapping in the "mm" passed to get_user_pages(). However it's non trivial change to pass the "pmd" status belonging to the "mm" walked by get_user_pages up the stack (up to the caller of get_user_pages). So the fix just checks if there is not a single pte mapping on the page returned by get_user_pages, and in turn if the caller can assume that the whole compound page is mapped in the current "mm" (in a pmd_trans_huge()). In such case the entire compound page is safe to map into the secondary MMU without additional get_user_pages() calls on the surrounding tail/head pages. In addition of being faster, not having to run other get_user_pages() calls also reduces the memory footprint of the secondary MMU fault in case the pmd split happened as result of memory pressure. Without this fix after a MADV_DONTNEED (like invoked by QEMU during postcopy live migration or balloning) or after generic swapping (with a failure in split_huge_page() that would only result in pmd splitting and not a physical page split), KVM would map the whole compound page into the shadow pagetables, despite regular faults or userfaults (like UFFDIO_COPY) may map regular pages into the primary MMU as result of the pte faults, leading to the guest mode and userland mode going out of sync and not working on the same memory at all times. Any other secondary MMU notifier manager (KVM is just one of the many MMU notifier users) will need the same information if it doesn't want to run a flood of get_user_pages_fast and it can support multiple granularity in the secondary MMU mappings, so I think it is justified to be exposed not just to KVM. The other option would be to move transparent_hugepage_adjust to mm/huge_memory.c but that currently has all kind of KVM data structures in it, so it's definitely not a cut-and-paste work, so I couldn't do a fix as cleaner as this one for 4.6. Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: "Li, Liang Z" <liang.z.li@intel.com> Cc: Amit Shah <amit.shah@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 4月, 2016 1 次提交
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由 Xiao Guangrong 提交于
The obsolete sp should not be used on current vCPUs and should not hurt vCPU's running, so skip it from for_each_gfn_sp() and for_each_gfn_indirect_valid_sp() The side effort is we will double check role.invalid in kvm_mmu_get_page() but i think it is okay as role is well cached Signed-off-by: NXiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 01 4月, 2016 1 次提交
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由 Yu Zhao 提交于
In absence of shadow dirty mask, there is no need to set page dirty if page has never been writable. This is a tiny optimization but good to have for people who care much about dirty page tracking. Signed-off-by: NYu Zhao <yuzhao@google.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 31 3月, 2016 1 次提交
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由 Borislav Petkov 提交于
Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1459266123-21878-6-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 22 3月, 2016 3 次提交
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由 Lan Tianyu 提交于
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Lan Tianyu 提交于
There is already a barrier inside of kvm_flush_remote_tlbs() which can help to make sure everyone sees our modifications to the page tables and see changes to vcpu->mode here. So remove the smp_mb in the kvm_mmu_commit_zap_page() and update the comment. Signed-off-by: NLan Tianyu <tianyu.lan@intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Huaitong Han 提交于
PKEYS defines a new status bit in the PFEC. PFEC.PK (bit 5), if some conditions is true, the fault is considered as a PKU violation. pkru_mask indicates if we need to check PKRU.ADi and PKRU.WDi, and does cache some conditions for permission_fault. [ Huaitong: Xiao helps to modify many sections. ] Signed-off-by: NHuaitong Han <huaitong.han@intel.com> Signed-off-by: NXiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 10 3月, 2016 1 次提交
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由 Paolo Bonzini 提交于
KVM has special logic to handle pages with pte.u=1 and pte.w=0 when CR0.WP=1. These pages' SPTEs flip continuously between two states: U=1/W=0 (user and supervisor reads allowed, supervisor writes not allowed) and U=0/W=1 (supervisor reads and writes allowed, user writes not allowed). When SMEP is in effect, however, U=0 will enable kernel execution of this page. To avoid this, KVM also sets NX=1 in the shadow PTE together with U=0, making the two states U=1/W=0/NX=gpte.NX and U=0/W=1/NX=1. When guest EFER has the NX bit cleared, the reserved bit check thinks that the latter state is invalid; teach it that the smep_andnot_wp case will also use the NX bit of SPTEs. Cc: stable@vger.kernel.org Reviewed-by: NXiao Guangrong <guangrong.xiao@linux.inel.com> Fixes: c258b62bSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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- 08 3月, 2016 3 次提交
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由 Paolo Bonzini 提交于
Branch-free code is fun and everybody knows how much Avi loves it, but last_pte_bitmap takes it a bit to the extreme. Since the code is simply doing a range check, like (level == 1 || ((gpte & PT_PAGE_SIZE_MASK) && level < N) we can make it branch-free without storing the entire truth table; it is enough to cache N. Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Paolo Bonzini 提交于
mmu_sync_children can only process up to 16 pages at a time. Check if we need to reschedule, and do not bother zapping the pages until that happens. Reviewed-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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由 Paolo Bonzini 提交于
kvm_mmu_get_page is the only caller of kvm_sync_page_transient and kvm_sync_pages. Moving the handling of the invalid_list there removes the need for the underdocumented kvm_sync_page_transient function. Reviewed-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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