summaryrefslogtreecommitdiff
path: root/arch/x86/kvm/paging_tmpl.h
AgeCommit message (Collapse)Author
2018-12-21KVM: Replace old tlb flush function with new one to flush a specified range.Lan Tianyu
This patch is to replace kvm_flush_remote_tlbs() with kvm_flush_ remote_tlbs_with_address() in some functions without logic change. Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.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>
2018-08-06kvm: x86: Add a root_hpa parameter to kvm_mmu->invlpg()Junaid Shahid
This allows invlpg() to be called using either the active root_hpa or the prev_root_hpa. Signed-off-by: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06kvm: x86: Make sync_page() flush remote TLBs once onlyJunaid Shahid
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: Junaid Shahid <junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-06KVM: MMU: drop vcpu param in gpte_accessPeter Xu
It's never used. Drop it. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-03-16KVM: x86: Update the exit_qualification access bits while walking an addressKarimAllah Ahmed
... to avoid having a stale value when handling an EPT misconfig for MMIO regions. MMIO regions that are not passed-through to the guest are handled through EPT misconfigs. The first time a certain MMIO page is touched it causes an EPT violation, then KVM marks the EPT entry to cause an EPT misconfig instead. Any subsequent accesses to the entry will generate an EPT misconfig. Things gets slightly complicated with nested guest handling for MMIO regions that are not passed through from L0 (i.e. emulated by L0 user-space). An EPT violation for one of these MMIO regions from L2, exits to L0 hypervisor. L0 would then look at the EPT12 mapping for L1 hypervisor and realize it is not present (or not sufficient to serve the request). Then L0 injects an EPT violation to L1. L1 would then update its EPT mappings. The EXIT_QUALIFICATION value for L1 would come from exit_qualification variable in "struct vcpu". The problem is that this variable is only updated on EPT violation and not on EPT misconfig. So if an EPT violation because of a read happened first, then an EPT misconfig because of a write happened afterwards. The L0 hypervisor will still contain exit_qualification value from the previous read instead of the write and end up injecting an EPT violation to the L1 hypervisor with an out of date EXIT_QUALIFICATION. The EPT violation that is injected from L0 to L1 needs to have the correct EXIT_QUALIFICATION specially for the access bits because the individual access bits for MMIO EPTs are updated only on actual access of this specific type. So for the example above, the L1 hypervisor will keep updating only the read bit in the EPT then resume the L2 guest. The L2 guest would end up causing another exit where the L0 *again* will inject another EPT violation to L1 hypervisor with *again* an out of date exit_qualification which indicates a read and not a write. Then this ping-pong just keeps happening without making any forward progress. The behavior of mapping MMIO regions changed in: commit a340b3e229b24 ("kvm: Map PFN-type memory regions as writable (if possible)") ... where an EPT violation for a read would also fixup the write bits to avoid another EPT violation which by acciddent would fix the bug mentioned above. This commit fixes this situation and ensures that the access bits for the exit_qualifcation is up to date. That ensures that even L1 hypervisor running with a KVM version before the commit mentioned above would still work. ( The description above assumes EPT to be available and used by L1 hypervisor + the L1 hypervisor is passing through the MMIO region to the L2 guest while this MMIO region is emulated by the L0 user-space ). 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: KarimAllah Ahmed <karahmed@amazon.de> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-10-12KVM: x86: extend usage of RET_MMIO_PF_* constantsPaolo Bonzini
The x86 MMU if full of code that returns 0 and 1 for retry/emulate. Use the existing RET_MMIO_PF_RETRY/RET_MMIO_PF_EMULATE enum, renaming it to drop the MMIO part. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-10-10KVM: MMU: always terminate page walks at level 1Ladi Prosek
is_last_gpte() is not equivalent to the pseudo-code given in commit 6bb69c9b69c31 ("KVM: MMU: simplify last_pte_bitmap") because an incorrect value of last_nonleaf_level may override the result even if level == 1. It is critical for is_last_gpte() to return true on level == 1 to terminate page walks. Otherwise memory corruption may occur as level is used as an index to various data structures throughout the page walking code. Even though the actual bug would be wherever the MMU is initialized (as in the previous patch), be defensive and ensure here that is_last_gpte() returns the correct value. This patch is also enough to fix CVE-2017-12188. Fixes: 6bb69c9b69c315200ddc2bc79aee14c0184cf5b2 Cc: stable@vger.kernel.org Cc: Andy Honig <ahonig@google.com> Signed-off-by: Ladi Prosek <lprosek@redhat.com> [Panic if walk_addr_generic gets an incorrect level; this is a serious bug and it's not worth a WARN_ON where the recovery path might hide further exploitable issues; suggested by Andrew Honig. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-18KVM: x86: fix use of L1 MMIO areas in nested guestsPaolo Bonzini
There is currently some confusion between nested and L1 GPAs. The assignment to "direct" in kvm_mmu_page_fault tries to fix that, but it is not enough. What this patch does is fence off the MMIO cache completely when using shadow nested page tables, since we have neither a GVA nor an L1 GPA to put in the cache. This also allows some simplifications in kvm_mmu_page_fault and FNAME(page_fault). The EPT misconfig likewise does not have an L1 GPA to pass to kvm_io_bus_write, so that must be skipped for guest mode. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> [Changed comment to say "GPAs" instead of "L1's physical addresses", as per David's review. - Radim] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-08-11KVM: MMU: Bail out immediately if there is no available mmu pageWanpeng Li
Bailing out immediately if there is no available mmu page to alloc. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-05-15KVM: nVMX: fix EPT permissions as reported in exit qualificationPaolo Bonzini
This fixes the new ept_access_test_read_only and ept_access_test_read_write testcases from vmx.flat. The problem is that gpte_access moves bits around to switch from EPT bit order (XWR) to ACC_*_MASK bit order (RWX). This results in an incorrect exit qualification. To fix this, make pt_access and pte_access operate on raw PTE values (only with NX flipped to mean "can execute") and call gpte_access at the end of the walk. This lets us use pte_access to compute the exit qualification with XWR bit order. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Xiao Guangrong <xiaoguangrong@tencent.com> Signed-off-by: Radim Krčmář <rkrcmar@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>
2017-04-07kvm: x86: MMU support for EPT accessed/dirty bitsPaolo Bonzini
This prepares the MMU paging code for EPT accessed and dirty bits, which can be enabled optionally at runtime. Code that updates the accessed and dirty bits will need a pointer to the struct kvm_mmu. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-07-14kvm: mmu: track read permission explicitly for shadow EPT page tablesBandan Das
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: Bandan Das <bsd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@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/x86: Call smp_wmb() before increasing tlbs_dirtyLan Tianyu
Update spte before increasing tlbs_dirty to make sure no tlb flush in lost after spte is zapped. This pairs with the barrier in the kvm_flush_remote_tlbs(). Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> 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>
2016-03-09Merge tag 'kvm-arm-for-4.6' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/ARM updates for 4.6 - VHE support so that we can run the kernel at EL2 on ARMv8.1 systems - PMU support for guests - 32bit world switch rewritten in C - Various optimizations to the vgic save/restore code Conflicts: include/uapi/linux/kvm.h
2016-03-08KVM: MMU: micro-optimize gpte_accessPaolo Bonzini
Avoid AND-NOT, most x86 processor lack an instruction for it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-08KVM: MMU: invert return value of mmu.sync_page and *kvm_sync_page*Paolo Bonzini
Return true if the page was synced (and the TLB must be flushed) and false if the page was zapped. Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: clear write-flooding on the fast path of tracked pageXiao Guangrong
If the page fault is caused by write access on write tracked page, the real shadow page walking is skipped, we lost the chance to clear write flooding for the page structure current vcpu is using Fix it by locklessly waking shadow page table to clear write flooding on the shadow page structure out of mmu-lock. So that we change the count to atomic_t Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-03KVM: MMU: let page fault handler be aware tracked pageXiao Guangrong
The page fault caused by write access on the write tracked page can not be fixed, it always need to be emulated. page_fault_handle_page_track() is the fast path we introduce here to skip holding mmu-lock and shadow page table walking However, if the page table is not present, it is worth making the page table entry present and readonly to make the read access happy mmu_need_write_protect() need to be cooked to avoid page becoming writable when making page table present or sync/prefetch shadow page table entries Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-25KVM: x86: MMU: fix ubsan index-out-of-range warningMike Krinkin
Ubsan reports the following warning due to a typo in update_accessed_dirty_bits template, the patch fixes the typo: [ 168.791851] ================================================================================ [ 168.791862] UBSAN: Undefined behaviour in arch/x86/kvm/paging_tmpl.h:252:15 [ 168.791866] index 4 is out of range for type 'u64 [4]' [ 168.791871] CPU: 0 PID: 2950 Comm: qemu-system-x86 Tainted: G O L 4.5.0-rc5-next-20160222 #7 [ 168.791873] Hardware name: LENOVO 23205NG/23205NG, BIOS G2ET95WW (2.55 ) 07/09/2013 [ 168.791876] 0000000000000000 ffff8801cfcaf208 ffffffff81c9f780 0000000041b58ab3 [ 168.791882] ffffffff82eb2cc1 ffffffff81c9f6b4 ffff8801cfcaf230 ffff8801cfcaf1e0 [ 168.791886] 0000000000000004 0000000000000001 0000000000000000 ffffffffa1981600 [ 168.791891] Call Trace: [ 168.791899] [<ffffffff81c9f780>] dump_stack+0xcc/0x12c [ 168.791904] [<ffffffff81c9f6b4>] ? _atomic_dec_and_lock+0xc4/0xc4 [ 168.791910] [<ffffffff81da9e81>] ubsan_epilogue+0xd/0x8a [ 168.791914] [<ffffffff81daafa2>] __ubsan_handle_out_of_bounds+0x15c/0x1a3 [ 168.791918] [<ffffffff81daae46>] ? __ubsan_handle_shift_out_of_bounds+0x2bd/0x2bd [ 168.791922] [<ffffffff811287ef>] ? get_user_pages_fast+0x2bf/0x360 [ 168.791954] [<ffffffffa1794050>] ? kvm_largepages_enabled+0x30/0x30 [kvm] [ 168.791958] [<ffffffff81128530>] ? __get_user_pages_fast+0x360/0x360 [ 168.791987] [<ffffffffa181b818>] paging64_walk_addr_generic+0x1b28/0x2600 [kvm] [ 168.792014] [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm] [ 168.792019] [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350 [ 168.792044] [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm] [ 168.792076] [<ffffffffa181c36d>] paging64_gva_to_gpa+0x7d/0x110 [kvm] [ 168.792121] [<ffffffffa181c2f0>] ? paging64_walk_addr_generic+0x2600/0x2600 [kvm] [ 168.792130] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792178] [<ffffffffa17d9a4a>] emulator_read_write_onepage+0x27a/0x1150 [kvm] [ 168.792208] [<ffffffffa1794d44>] ? __kvm_read_guest_page+0x54/0x70 [kvm] [ 168.792234] [<ffffffffa17d97d0>] ? kvm_task_switch+0x160/0x160 [kvm] [ 168.792238] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792263] [<ffffffffa17daa07>] emulator_read_write+0xe7/0x6d0 [kvm] [ 168.792290] [<ffffffffa183b620>] ? em_cr_write+0x230/0x230 [kvm] [ 168.792314] [<ffffffffa17db005>] emulator_write_emulated+0x15/0x20 [kvm] [ 168.792340] [<ffffffffa18465f8>] segmented_write+0xf8/0x130 [kvm] [ 168.792367] [<ffffffffa1846500>] ? em_lgdt+0x20/0x20 [kvm] [ 168.792374] [<ffffffffa14db512>] ? vmx_read_guest_seg_ar+0x42/0x1e0 [kvm_intel] [ 168.792400] [<ffffffffa1846d82>] writeback+0x3f2/0x700 [kvm] [ 168.792424] [<ffffffffa1846990>] ? em_sidt+0xa0/0xa0 [kvm] [ 168.792449] [<ffffffffa185554d>] ? x86_decode_insn+0x1b3d/0x4f70 [kvm] [ 168.792474] [<ffffffffa1859032>] x86_emulate_insn+0x572/0x3010 [kvm] [ 168.792499] [<ffffffffa17e71dd>] x86_emulate_instruction+0x3bd/0x2110 [kvm] [ 168.792524] [<ffffffffa17e6e20>] ? reexecute_instruction.part.110+0x2e0/0x2e0 [kvm] [ 168.792532] [<ffffffffa14e9a81>] handle_ept_misconfig+0x61/0x460 [kvm_intel] [ 168.792539] [<ffffffffa14e9a20>] ? handle_pause+0x450/0x450 [kvm_intel] [ 168.792546] [<ffffffffa15130ea>] vmx_handle_exit+0xd6a/0x1ad0 [kvm_intel] [ 168.792572] [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm] [ 168.792597] [<ffffffffa17f6bcd>] kvm_arch_vcpu_ioctl_run+0xd3d/0x6090 [kvm] [ 168.792621] [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm] [ 168.792627] [<ffffffff8293b530>] ? __ww_mutex_lock_interruptible+0x1630/0x1630 [ 168.792651] [<ffffffffa17f5e90>] ? kvm_arch_vcpu_runnable+0x4f0/0x4f0 [kvm] [ 168.792656] [<ffffffff811eeb30>] ? preempt_notifier_unregister+0x190/0x190 [ 168.792681] [<ffffffffa17e0447>] ? kvm_arch_vcpu_load+0x127/0x650 [kvm] [ 168.792704] [<ffffffffa178e9a3>] kvm_vcpu_ioctl+0x553/0xda0 [kvm] [ 168.792727] [<ffffffffa178e450>] ? vcpu_put+0x40/0x40 [kvm] [ 168.792732] [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350 [ 168.792735] [<ffffffff82946087>] ? _raw_spin_unlock+0x27/0x40 [ 168.792740] [<ffffffff8163a943>] ? handle_mm_fault+0x1673/0x2e40 [ 168.792744] [<ffffffff8129daa8>] ? trace_hardirqs_on_caller+0x478/0x6c0 [ 168.792747] [<ffffffff8129dcfd>] ? trace_hardirqs_on+0xd/0x10 [ 168.792751] [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90 [ 168.792756] [<ffffffff81725a80>] do_vfs_ioctl+0x1b0/0x12b0 [ 168.792759] [<ffffffff817258d0>] ? ioctl_preallocate+0x210/0x210 [ 168.792763] [<ffffffff8174aef3>] ? __fget+0x273/0x4a0 [ 168.792766] [<ffffffff8174acd0>] ? __fget+0x50/0x4a0 [ 168.792770] [<ffffffff8174b1f6>] ? __fget_light+0x96/0x2b0 [ 168.792773] [<ffffffff81726bf9>] SyS_ioctl+0x79/0x90 [ 168.792777] [<ffffffff82946880>] entry_SYSCALL_64_fastpath+0x23/0xc1 [ 168.792780] ================================================================================ Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-23KVM: x86: MMU: Move handle_mmio_page_fault() call to kvm_mmu_page_fault()Takuya Yoshikawa
Rather than placing a handle_mmio_page_fault() call in each vcpu->arch.mmu.page_fault() handler, moving it up to kvm_mmu_page_fault() makes the code better: - avoids code duplication - for kvm_arch_async_page_ready(), which is the other caller of vcpu->arch.mmu.page_fault(), removes an extra error_code check - avoids returning both RET_MMIO_PF_* values and raw integer values from vcpu->arch.mmu.page_fault() Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-01-15kvm: rename pfn_t to kvm_pfn_tDan Williams
To date, we have implemented two I/O usage models for persistent memory, PMEM (a persistent "ram disk") and DAX (mmap persistent memory into userspace). This series adds a third, DAX-GUP, that allows DAX mappings to be the target of direct-i/o. It allows userspace to coordinate DMA/RDMA from/to persistent memory. The implementation leverages the ZONE_DEVICE mm-zone that went into 4.3-rc1 (also discussed at kernel summit) to flag pages that are owned and dynamically mapped by a device driver. The pmem driver, after mapping a persistent memory range into the system memmap via devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus page-backed pmem-pfns via flags in the new pfn_t type. The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the resulting pte(s) inserted into the process page tables with a new _PAGE_DEVMAP flag. Later, when get_user_pages() is walking ptes it keys off _PAGE_DEVMAP to pin the device hosting the page range active. Finally, get_page() and put_page() are modified to take references against the device driver established page mapping. Finally, this need for "struct page" for persistent memory requires memory capacity to store the memmap array. Given the memmap array for a large pool of persistent may exhaust available DRAM introduce a mechanism to allocate the memmap from persistent memory. The new "struct vmem_altmap *" parameter to devm_memremap_pages() enables arch_add_memory() to use reserved pmem capacity rather than the page allocator. This patch (of 18): The core has developed a need for a "pfn_t" type [1]. Move the existing pfn_t in KVM to kvm_pfn_t [2]. [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html [2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-26KVM: x86: MMU: Remove unused parameter parent_pte from kvm_mmu_get_page()Takuya Yoshikawa
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-26KVM: x86: MMU: Move parent_pte handling from kvm_mmu_get_page() to ↵Takuya Yoshikawa
link_shadow_page() Every time kvm_mmu_get_page() is called with a non-NULL parent_pte argument, link_shadow_page() follows that to set the parent entry so that the new mapping will point to the returned page table. Moving parent_pte handling there allows to clean up the code because parent_pte is passed to kvm_mmu_get_page() just for mark_unsync() and mmu_page_add_parent_pte(). In addition, the patch avoids calling mark_unsync() for other parents in the sp->parent_ptes chain than the newly added parent_pte, because they have been there since before the current page fault handling started. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-25KVM: x86: MMU: Make mmu_set_spte() return emulate valueTakuya Yoshikawa
mmu_set_spte()'s code is based on the assumption that the emulate parameter has a valid pointer value if set_spte() returns true and write_fault is not zero. In other cases, emulate may be NULL, so a NULL-check is needed. Stop passing emulate pointer and make mmu_set_spte() return the emulate value instead to clean up this complex interface. Prefetch functions can just throw away the return value. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-25KVM: x86: MMU: always set accessed bit in shadow PTEsPaolo Bonzini
Commit 7a1638ce4220 ("nEPT: Redefine EPT-specific link_shadow_page()", 2013-08-05) says: Since nEPT doesn't support A/D bit, we should not set those bit when building the shadow page table. but this is not necessary. Even though nEPT doesn't support A/D bits, and hence the vmcs12 EPT pointer will never enable them, we always use them for shadow page tables if available (see construct_eptp in vmx.c). So we can set the A/D bits freely in the shadow page table. This patch hence basically reverts commit 7a1638ce4220. Cc: Yang Zhang <yang.z.zhang@Intel.com> Cc: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> 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>
2015-10-19KVM: x86: MMU: Initialize force_pt_level before calling mapping_level()Takuya Yoshikawa
Commit fd1369021878 ("KVM: x86: MMU: Move mapping_level_dirty_bitmap() call in mapping_level()") forgot to initialize force_pt_level to false in FNAME(page_fault)() before calling mapping_level() like nonpaging_map() does. This can sometimes result in forcing page table level mapping unnecessarily. Fix this and move the first *force_pt_level check in mapping_level() before kvm_vcpu_gfn_to_memslot() call to make it a bit clearer that the variable must be initialized before mapping_level() gets called. This change can also avoid calling kvm_vcpu_gfn_to_memslot() when !check_hugepage_cache_consistency() check in tdp_page_fault() forces page table level mapping. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16KVM: x86: MMU: Move mapping_level_dirty_bitmap() call in mapping_level()Takuya Yoshikawa
This is necessary to eliminate an extra memory slot search later. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16KVM: x86: MMU: Simplify force_pt_level calculation code in FNAME(page_fault)()Takuya Yoshikawa
As a bonus, an extra memory slot search can be eliminated when is_self_change_mapping is true. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-10-16KVM: x86: MMU: Make force_pt_level boolTakuya Yoshikawa
This will be passed to a function later. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-08-05KVM: MMU: move FNAME(is_rsvd_bits_set) to mmu.cXiao Guangrong
FNAME(is_rsvd_bits_set) does not depend on guest mmu mode, move it to mmu.c to stop being compiled multiple times Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-05KVM: x86: use vcpu-specific functions to read/write/translate GFNsPaolo Bonzini
We need to hide SMRAM from guests not running in SMM. Therefore, all uses of kvm_read_guest* and kvm_write_guest* must be changed to check whether the VCPU is in system management mode and use a different set of memslots. Switch from kvm_* to the newly-introduced kvm_vcpu_*, which call into kvm_arch_vcpu_memslots_id. Reviewed-by: Radim Krčmář <rkrcmar@redhat.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>
2014-10-24KVM: x86: Wrong assertion on paging_tmpl.hNadav Amit
Even after the recent fix, the assertion on paging_tmpl.h is triggered. Apparently, the assertion wants to check that the PAE is always set on long-mode, but does it in incorrect way. Note that the assertion is not enabled unless the code is debugged by defining MMU_DEBUG. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-24KVM: x86: Remove debug assertion of non-PAE reserved bitsNadav Amit
Commit 346874c9507a ("KVM: x86: Fix CR3 reserved bits") removed non-PAE reserved bits which were not according to Intel SDM. However, residue was left in a debug assertion (CR3_NONPAE_RESERVED_BITS). Remove it. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-05KVM: x86: propagate exception from permission checks on the nested page faultPaolo Bonzini
Currently, if a permission error happens during the translation of the final GPA to HPA, walk_addr_generic returns 0 but does not fill in walker->fault. To avoid this, add an x86_exception* argument to the translate_gpa function, and let it fill in walker->fault. The nested_page_fault field will be true, since the walk_mmu is the nested_mmu and translate_gpu instead operates on the "outer" (NPT) instance. Reported-by: Valentine Sinitsyn <valentine.sinitsyn@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-09-03KVM: nSVM: propagate the NPF EXITINFO to the guestPaolo Bonzini
This is similar to what the EPT code does with the exit qualification. This allows the guest to see a valid value for bits 33:32. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-04-23Revert "KVM: Simplify kvm->tlbs_dirty handling"Xiao Guangrong
This reverts commit 5befdc385ddb2d5ae8995ad89004529a3acf58fc. Since we will allow flush tlb out of mmu-lock in the later patch 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>
2014-02-18KVM: Simplify kvm->tlbs_dirty handlingTakuya Yoshikawa
When this was introduced, kvm_flush_remote_tlbs() could be called without holding mmu_lock. It is now acknowledged that the function must be called before releasing mmu_lock, and all callers have already been changed to do so. There is no need to use smp_mb() and cmpxchg() any more. Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-01-15KVM: x86: handle invalid root_hpa everywhereMarcelo Tosatti
Rom Freiman <rom@stratoscale.com> notes other code paths vulnerable to bug fixed by 989c6b34f6a9480e397b. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-09-17KVM: mmu: allow page tables to be in read-only slotsPaolo Bonzini
Page tables in a read-only memory slot will currently cause a triple fault because the page walker uses gfn_to_hva and it fails on such a slot. OVMF uses such a page table; however, real hardware seems to be fine with that as long as the accessed/dirty bits are set. Save whether the slot is readonly, and later check it when updating the accessed and dirty bits. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-08-07nEPT: Add nEPT violation/misconfigration supportYang Zhang
Inject nEPT fault to L1 guest. This patch is original from Xinhao. Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.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>