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2010-08-02KVM: MMU: invalidate and flush on spte small->large page size changeMarcelo Tosatti
Always invalidate spte and flush TLBs when changing page size, to make sure different sized translations for the same address are never cached in a CPU's TLB. Currently the only case where this occurs is when a non-leaf spte pointer is overwritten by a leaf, large spte entry. This can happen after dirty logging is disabled on a memslot, for example. Noticed by Andrea. KVM-Stable-Tag Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com> (cherry picked from commit 3be2264be3c00865116f997dc53ebcc90fe7fc4b)
2010-08-02KVM: MMU: Remove user access when allowing kernel access to gpte.w=0 pageAvi Kivity
If cr0.wp=0, we have to allow the guest kernel access to a page with pte.w=0. We do that by setting spte.w=1, since the host cr0.wp must remain set so the host can write protect pages. Once we allow write access, we must remove user access otherwise we mistakenly allow the user to write the page. Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com> (cherry picked from commit 69325a122580d3a7b26589e8efdd6663001c3297)
2010-07-05KVM: MMU: Don't read pdptrs with mmu spinlock held in mmu_alloc_rootsAvi Kivity
On svm, kvm_read_pdptr() may require reading guest memory, which can sleep. Push the spinlock into mmu_alloc_roots(), and only take it after we've read the pdptr. Tested-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> (cherry picked from commit 8facbbff071ff2b19268d3732e31badc60471e21)
2010-07-05KVM: MMU: Segregate shadow pages with different cr0.wpAvi Kivity
When cr0.wp=0, we may shadow a gpte having u/s=1 and r/w=0 with an spte having u/s=0 and r/w=1. This allows excessive access if the guest sets cr0.wp=1 and accesses through this spte. Fix by making cr0.wp part of the base role; we'll have different sptes for the two cases and the problem disappears. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> (cherry picked from commit 3dbe141595faa48a067add3e47bba3205b79d33c)
2010-04-26KVM: MMU: fix kvm_mmu_zap_page() and its calling pathXiao Guangrong
(Cherry-picked from commit 77662e0028c7c63e34257fda03ff9625c59d939d) This patch fix: - calculate zapped page number properly in mmu_zap_unsync_children() - calculate freeed page number properly kvm_mmu_change_mmu_pages() - if zapped children page it shoud restart hlist walking KVM-Stable-Tag. Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-04-26KVM: x86 emulator: fix memory access during x86 emulationGleb Natapov
commit 1871c6020d7308afb99127bba51f04548e7ca84e upstream Currently when x86 emulator needs to access memory, page walk is done with broadest permission possible, so if emulated instruction was executed by userspace process it can still access kernel memory. Fix that by providing correct memory access to page walker during emulation. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-01-28KVM: x86: Fix host_mapping_level()Sheng Yang
commit 82b7005f0e72d8d1a8226e4c192cbb0850d10b3f upstream. When found a error hva, should not return PAGE_SIZE but the level... Also clean up the coding style of the following loop. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-10-16KVM: MMU: fix pointer castFrederik Deweerdt
On a 32 bits compile, commit 3da0dd433dc399a8c0124d0614d82a09b6a49bce introduced the following warnings: arch/x86/kvm/mmu.c: In function ‘kvm_set_pte_rmapp’: arch/x86/kvm/mmu.c:770: warning: cast to pointer from integer of different size arch/x86/kvm/mmu.c: In function ‘kvm_set_spte_hva’: arch/x86/kvm/mmu.c:849: warning: cast from pointer to integer of different size The following patch uses 'unsigned long' instead of u64 to match the pointer size on both arches. Signed-off-by: Frederik Deweerdt <frederik.deweerdt@xprog.eu> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-10-04KVM: add support for change_pte mmu notifiersIzik Eidus
this is needed for kvm if it want ksm to directly map pages into its shadow page tables. [marcelo: cast pfn assignment to u64] Signed-off-by: Izik Eidus <ieidus@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-10-04KVM: MMU: add SPTE_HOST_WRITEABLE flag to the shadow ptesIzik Eidus
this flag notify that the host physical page we are pointing to from the spte is write protected, and therefore we cant change its access to be write unless we run get_user_pages(write = 1). (this is needed for change_pte support in kvm) Signed-off-by: Izik Eidus <ieidus@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-10-04KVM: MMU: dont hold pagecount reference for mapped sptes pagesIzik Eidus
When using mmu notifiers, we are allowed to remove the page count reference tooken by get_user_pages to a specific page that is mapped inside the shadow page tables. This is needed so we can balance the pagecount against mapcount checking. (Right now kvm increase the pagecount and does not increase the mapcount when mapping page into shadow page table entry, so when comparing pagecount against mapcount, you have no reliable result.) Signed-off-by: Izik Eidus <ieidus@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10KVM: Optimize kvm_mmu_unprotect_page_virt() for tdpAvi Kivity
We know no pages are protected, so we can short-circuit the whole thing (including fairly nasty guest memory accesses). Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: fix bogus alloc_mmu_pages assignmentMarcelo Tosatti
Remove the bogus n_free_mmu_pages assignment from alloc_mmu_pages. It breaks accounting of mmu pages, since n_free_mmu_pages is modified but the real number of pages remains the same. Cc: stable@kernel.org Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: make __kvm_mmu_free_some_pages handle empty listIzik Eidus
First check if the list is empty before attempting to look at list entries. Cc: stable@kernel.org Signed-off-by: Izik Eidus <ieidus@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: shadow support for 1gb pagesJoerg Roedel
This patch adds support for shadow paging to the 1gb page table code in KVM. With this code the guest can use 1gb pages even if the host does not support them. [ Marcelo: fix shadow page collision on pmd level if a guest 1gb page is mapped with 4kb ptes on host level ] Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: make page walker aware of mapping levelsJoerg Roedel
The page walker may be used with nested paging too when accessing mmio areas. Make it support the additional page-level too. [ Marcelo: fix reserved bit check for 1gb pte ] Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: make direct mapping paths aware of mapping levelsJoerg Roedel
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: rename is_largepage_backed to mapping_levelJoerg Roedel
With the new name and the corresponding backend changes this function can now support multiple hugepage sizes. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: make rmap code aware of mapping levelsJoerg Roedel
This patch removes the largepage parameter from the rmap_add function. Together with rmap_remove this function now uses the role.level field to find determine if the page is a huge page. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: fix missing locking in alloc_mmu_pagesMarcelo Tosatti
n_requested_mmu_pages/n_free_mmu_pages are used by kvm_mmu_change_mmu_pages to calculate the number of pages to zap. alloc_mmu_pages, called from the vcpu initialization path, modifies this variables without proper locking, which can result in a negative value in kvm_mmu_change_mmu_pages (say, with cpu hotplug). Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10KVM: Discard unnecessary kvm_mmu_flush_tlb() in kvm_mmu_load()Sheng Yang
set_cr3() should already cover the TLB flushing. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10KVM: MMU: Fix MMU_DEBUG compile breakageJoerg Roedel
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Trace shadow page lifecycleAvi Kivity
Create, sync, unsync, zap. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: Trace guest pagetable walkerAvi Kivity
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Prepare memslot data structures for multiple hugepage sizesJoerg Roedel
[avi: fix build on non-x86] Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: add kvm_mmu_get_spte_hierarchy helperMarcelo Tosatti
Required by EPT misconfiguration handler. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: make for_each_shadow_entry aware of largepagesMarcelo Tosatti
This way there is no need to add explicit checks in every for_each_shadow_entry user. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU audit: largepage handlingMarcelo Tosatti
Make the audit code aware of largepages. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU audit: audit_mappings tweaksMarcelo Tosatti
- Fail early in case gfn_to_pfn returns is_error_pfn. - For the pre pte write case, avoid spurious "gva is valid but spte is notrap" messages (the emulation code does the guest write first, so this particular case is OK). Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU audit: nontrapping ptes in nonleaf levelMarcelo Tosatti
It is valid to set non leaf sptes as notrap. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU audit: update audit_write_protectionMarcelo Tosatti
- Unsync pages contain writable sptes in the rmap. - rmaps do not exclusively contain writable sptes anymore. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU audit: update count_writable_mappings / count_rmapsMarcelo Tosatti
Under testing, count_writable_mappings returns a value that is 2 integers larger than what count_rmaps returns. Suspicion is that either of the two functions is counting a duplicate (either positively or negatively). Modifying check_writable_mappings_rmap to check for rmap existance on all present MMU pages fails to trigger an error, which should keep Avi happy. Also introduce mmu_spte_walk to invoke a callback on all present sptes visible to the current vcpu, might be useful in the future. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: introduce is_last_spte helperMarcelo Tosatti
Hiding some of the last largepage / level interaction (which is useful for gbpages and for zero based levels). Also merge the PT_PAGE_TABLE_LEVEL clearing loop in unlink_children. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Return to userspace on emulation failureAvi Kivity
Instead of mindlessly retrying to execute the instruction, report the failure to userspace. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Use macro to iterate over vcpus.Gleb Natapov
[christian: remove unused variables on s390] Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: s/shadow_pte/spte/Avi Kivity
We use shadow_pte and spte inconsistently, switch to the shorter spelling. Rename set_shadow_pte() to __set_spte() to avoid a conflict with the existing set_spte(), and to indicate its lowlevelness. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: Adjust pte accessors to explicitly indicate guest or shadow pteAvi Kivity
Since the guest and host ptes can have wildly different format, adjust the pte accessor names to indicate on which type of pte they operate on. No functional changes. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: MMU: Fix is_dirty_pte()Avi Kivity
is_dirty_pte() is used on guest ptes, not shadow ptes, so it needs to avoid shadow_dirty_mask and use PT_DIRTY_MASK instead. Misdetecting dirty pages could lead to unnecessarily setting the dirty bit under EPT. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10KVM: Cache pdptrsAvi Kivity
Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx, guest memory access on svm) extract them on demand. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-06KVM: MMU: limit rmap chain lengthMarcelo Tosatti
Otherwise the host can spend too long traversing an rmap chain, which happens under a spinlock. Cc: stable@kernel.org Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-05KVM: MMU: handle n_free_mmu_pages > n_alloc_mmu_pages in ↵Marcelo Tosatti
kvm_mmu_change_mmu_pages kvm_mmu_change_mmu_pages mishandles the case where n_alloc_mmu_pages is smaller then n_free_mmu_pages, by not checking if the result of the subtraction is negative. Its a valid condition which can happen if a large number of pages has been recently freed. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-28KVM: MMU: Allow 4K ptes with bit 7 (PAT) setAvi Kivity
Bit 7 is perfectly legal in the 4K page leve; it is used for the PAT. Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: x86: check for cr3 validity in mmu_alloc_rootsMarcelo Tosatti
Verify the cr3 address stored in vcpu->arch.cr3 points to an existant memslot. If not, inject a triple fault. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: MMU: protect kvm_mmu_change_mmu_pages with mmu_lockMarcelo Tosatti
kvm_handle_hva, called by MMU notifiers, manipulates mmu data only with the protection of mmu_lock. Update kvm_mmu_change_mmu_pages callers to take mmu_lock, thus protecting against kvm_handle_hva. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: Replace get_mt_mask_shift with get_mt_maskSheng Yang
Shadow_mt_mask is out of date, now it have only been used as a flag to indicate if TDP enabled. Get rid of it and use tdp_enabled instead. Also put memory type logical in kvm_x86_ops->get_mt_mask(). Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: MMU: Fix auditing codeJan Kiszka
Fix build breakage of hpa lookup in audit_mappings_page. Moreover, make this function robust against shadow_notrap_nonpresent_pte entries. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: MMU: remove global page optimization logicMarcelo Tosatti
Complexity to fix it not worthwhile the gains, as discussed in http://article.gmane.org/gmane.comp.emulators.kvm.devel/28649. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: MMU: Discard reserved bits checking on PDE bit 7-8Sheng Yang
1. It's related to a Linux kernel bug which fixed by Ingo on 07a66d7c53a538e1a9759954a82bb6c07365eff9. The original code exists for quite a long time, and it would convert a PDE for large page into a normal PDE. But it fail to fit normal PDE well. With the code before Ingo's fix, the kernel would fall reserved bit checking with bit 8 - the remaining global bit of PTE. So the kernel would receive a double-fault. 2. After discussion, we decide to discard PDE bit 7-8 reserved checking for now. For this marked as reserved in SDM, but didn't checked by the processor in fact... Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: Use rsvd_bits_mask in load_pdptrs()Dong, Eddie
Also remove bit 5-6 from rsvd_bits_mask per latest SDM. Signed-off-by: Eddie Dong <Eddie.Dong@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10KVM: MMU: Emulate #PF error code of reserved bits violationDong, Eddie
Detect, indicate, and propagate page faults where reserved bits are set. Take care to handle the different paging modes, each of which has different sets of reserved bits. [avi: fix pte reserved bits for efer.nxe=0] Signed-off-by: Eddie Dong <eddie.dong@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
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