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2017-02-17KVM: PPC: Book3S PR: Ratelimit copy data failure error messagesVipin K Parashar1-1/+2
kvm_ppc_mmu_book3s_32/64 xlat() logs "KVM can't copy data" error upon failing to copy user data to kernel space. This floods kernel log once such fails occur in short time period. Ratelimit this error to avoid flooding kernel logs upon copy data failures. Signed-off-by: Vipin K Parashar <vipin@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2014-12-17arch: powerpc: kvm: book3s_32_mmu.c: Remove unused functionRickard Strandqvist1-5/+0
Remove the function sr_nx() that is not used anywhere. This was partially found by using a static code analysis program called cppcheck. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28KVM: PPC: Book3S: Stop PTE lookup on write errorsAlexander Graf1-1/+1
When a page lookup failed because we're not allowed to write to the page, we should not overwrite that value with another lookup on the second PTEG which will return "page not found". Instead, we should just tell the caller that we had a permission problem. This fixes Mac OS X guests looping endlessly in page lookup code for me. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-30KVM: PPC: Book3S PR: Do dcbz32 patching with big endian instructionsAlexander Graf1-1/+1
When the host CPU we're running on doesn't support dcbz32 itself, but the guest wants to have dcbz only clear 32 bytes of data, we loop through every executable mapped page to search for dcbz instructions and patch them with a special privileged instruction that we emulate as dcbz32. The only guests that want to see dcbz act as 32byte are book3s_32 guests, so we don't have to worry about little endian instruction ordering. So let's just always search for big endian dcbz instructions, also when we're on a little endian host. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-30KVM: PPC: Make shared struct aka magic page guest endianAlexander Graf1-10/+11
The shared (magic) page is a data structure that contains often used supervisor privileged SPRs accessible via memory to the user to reduce the number of exits we have to take to read/write them. When we actually share this structure with the guest we have to maintain it in guest endianness, because some of the patch tricks only work with native endian load/store operations. Since we only share the structure with either host or guest in little endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv. For booke, the shared struct stays big endian. For book3s_64 hv we maintain the struct in host native endian, since it never gets shared with the guest. For book3s_64 pr we introduce a variable that tells us which endianness the shared struct is in and route every access to it through helper inline functions that evaluate this variable. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-30KVM: PPC: Book3S_32: PR: Access HTAB in big endianAlexander Graf1-6/+10
The HTAB is always big endian. We access the guest's HTAB using copy_from/to_user, but don't yet take care of the fact that we might be running on an LE host. Wrap all accesses to the guest HTAB with big endian accessors. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-30KVM: PPC: Book3S: PR: Fix C/R bit settingAlexander Graf1-1/+1
Commit 9308ab8e2d made C/R HTAB updates go byte-wise into the target HTAB. However, it didn't update the guest's copy of the HTAB, but instead the host local copy of it. Write to the guest's HTAB instead. Signed-off-by: Alexander Graf <agraf@suse.de> CC: Paul Mackerras <paulus@samba.org> Acked-by: Paul Mackerras <paulus@samba.org>
2013-10-17KVM: PPC: Book3S PR: Better handling of host-side read-only pagesPaul Mackerras1-15/+17
Currently we request write access to all pages that get mapped into the guest, even if the guest is only loading from the page. This reduces the effectiveness of KSM because it means that we unshare every page we access. Also, we always set the changed (C) bit in the guest HPTE if it allows writing, even for a guest load. This fixes both these problems. We pass an 'iswrite' flag to the mmu.xlate() functions and to kvmppc_mmu_map_page() to indicate whether the access is a load or a store. The mmu.xlate() functions now only set C for stores. kvmppc_gfn_to_pfn() now calls gfn_to_pfn_prot() instead of gfn_to_pfn() so that it can indicate whether we need write access to the page, and get back a 'writable' flag to indicate whether the page is writable or not. If that 'writable' flag is clear, we then make the host HPTE read-only even if the guest HPTE allowed writing. This means that we can get a protection fault when the guest writes to a page that it has mapped read-write but which is read-only on the host side (perhaps due to KSM having merged the page). Thus we now call kvmppc_handle_pagefault() for protection faults as well as HPTE not found faults. In kvmppc_handle_pagefault(), if the access was allowed by the guest HPTE and we thus need to install a new host HPTE, we then need to remove the old host HPTE if there is one. This is done with a new function, kvmppc_mmu_unmap_page(), which uses kvmppc_mmu_pte_vflush() to find and remove the old host HPTE. Since the memslot-related functions require the KVM SRCU read lock to be held, this adds srcu_read_lock/unlock pairs around the calls to kvmppc_handle_pagefault(). Finally, this changes kvmppc_mmu_book3s_32_xlate_pte() to not ignore guest HPTEs that don't permit access, and to return -EPERM for accesses that are not permitted by the page protections. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17KVM: PPC: Book3S PR: Allocate kvm_vcpu structs from kvm_vcpu_cachePaul Mackerras1-4/+4
This makes PR KVM allocate its kvm_vcpu structs from the kvm_vcpu_cache rather than having them embedded in the kvmppc_vcpu_book3s struct, which is allocated with vzalloc. The reason is to reduce the differences between PR and HV KVM in order to make is easier to have them coexist in one kernel binary. With this, the kvm_vcpu struct has a pointer to the kvmppc_vcpu_book3s struct. The pointer to the kvmppc_book3s_shadow_vcpu struct has moved from the kvmppc_vcpu_book3s struct to the kvm_vcpu struct, and is only present for 32-bit, since it is only used for 32-bit. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: squash in compile fix from Aneesh] Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17KVM: PPC: Book3S PR: Make HPT accesses and updates SMP-safePaul Mackerras1-14/+22
This adds a per-VM mutex to provide mutual exclusion between vcpus for accesses to and updates of the guest hashed page table (HPT). This also makes the code use single-byte writes to the HPT entry when updating of the reference (R) and change (C) bits. The reason for doing this, rather than writing back the whole HPTE, is that on non-PAPR virtual machines, the guest OS might be writing to the HPTE concurrently, and writing back the whole HPTE might conflict with that. Also, real hardware does single-byte writes to update R and C. The new mutex is taken in kvmppc_mmu_book3s_64_xlate() when reading the HPT and updating R and/or C, and in the PAPR HPT update hcalls (H_ENTER, H_REMOVE, etc.). Having the mutex means that we don't need to use a hypervisor lock bit in the HPT update hcalls, and we don't need to be careful about the order in which the bytes of the HPTE are updated by those hcalls. The other change here is to make emulated TLB invalidations (tlbie) effective across all vcpus. To do this we call kvmppc_mmu_pte_vflush for all vcpus in kvmppc_ppc_book3s_64_tlbie(). For 32-bit, this makes the setting of the accessed and dirty bits use single-byte writes, and makes tlbie invalidate shadow HPTEs for all vcpus. With this, PR KVM can successfully run SMP guests. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17KVM: PPC: Book3S PR: Use 64k host pages where possiblePaul Mackerras1-0/+1
Currently, PR KVM uses 4k pages for the host-side mappings of guest memory, regardless of the host page size. When the host page size is 64kB, we might as well use 64k host page mappings for guest mappings of 64kB and larger pages and for guest real-mode mappings. However, the magic page has to remain a 4k page. To implement this, we first add another flag bit to the guest VSID values we use, to indicate that this segment is one where host pages should be mapped using 64k pages. For segments with this bit set we set the bits in the shadow SLB entry to indicate a 64k base page size. When faulting in host HPTEs for this segment, we make them 64k HPTEs instead of 4k. We record the pagesize in struct hpte_cache for use when invalidating the HPTE. For now we restrict the segment containing the magic page (if any) to 4k pages. It should be possible to lift this restriction in future by ensuring that the magic 4k page is appropriately positioned within a host 64k page. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24KVM: PPC: Put segment registers in shared pageAlexander Graf1-6/+6
Now that the actual mtsr doesn't do anything anymore, we can move the sr contents over to the shared page, so a guest can directly read and write its sr contents from guest context. Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24KVM: PPC: Interpret SR registers on demandAlexander Graf1-36/+43
Right now we're examining the contents of Book3s_32's segment registers when the register is written and put the interpreted contents into a struct. There are two reasons this is bad. For starters, the struct has worse real-time performance, as it occupies more ram. But the more important part is that with segment registers being interpreted from their raw values, we can put them in the shared page, allowing guests to mess with them directly. This patch makes the internal representation of SRs be u32s. Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24KVM: PPC: Book3S_32 MMU debug compile fixesAlexander Graf1-2/+2
Due to previous changes, the Book3S_32 guest MMU code didn't compile properly when enabling debugging. This patch repairs the broken code paths, making it possible to define DEBUG_MMU and friends again. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24KVM: PPC: Magic Page Book3s supportAlexander Graf1-0/+16
We need to override EA as well as PA lookups for the magic page. When the guest tells us to project it, the magic page overrides any guest mappings. In order to reflect that, we need to hook into all the MMU layers of KVM to force map the magic page if necessary. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24KVM: PPC: Convert MSR to shared pageAlexander Graf1-6/+6
One of the most obvious registers to share with the guest directly is the MSR. The MSR contains the "interrupts enabled" flag which the guest has to toggle in critical sections. So in order to bring the overhead of interrupt en- and disabling down, let's put msr into the shared page. Keep in mind that even though you can fully read its contents, writing to it doesn't always update all state. There are a few safe fields that don't require hypervisor interaction. See the documentation for a list of MSR bits that are safe to be set from inside the guest. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01KVM: PPC: Make BAT only guest segments workAlexander Graf1-4/+4
When a guest sets its SR entry to invalid, we may still find a corresponding entry in a BAT. So we need to make sure we're not faulting on invalid SR entries, but instead just claim them to be BAT resolved. This resolves breakage experienced when using libogc based guests. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Improve split modeAlexander Graf1-8/+13
When in split mode, instruction relocation and data relocation are not equal. So far we implemented this mode by reserving a special pseudo-VSID for the two cases and flushing all PTEs when going into split mode, which is slow. Unfortunately 32bit Linux and Mac OS X use split mode extensively. So to not slow down things too much, I came up with a different idea: Mark the split mode with a bit in the VSID and then treat it like any other segment. This means we can just flush the shadow segment cache, but keep the PTEs intact. I verified that this works with ppc32 Linux and Mac OS X 10.4 guests and does speed them up. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Convert u64 -> ulongAlexander Graf1-3/+3
There are some pieces in the code that I overlooked that still use u64s instead of longs. This slows down 32 bit hosts unnecessarily, so let's just move them to ulong. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Add Book3S compatibility codeAlexander Graf1-0/+3
Some code we had so far required defines and had code that was completely Book3S_64 specific. Since we now opened book3s.c to Book3S_32 too, we need to take care of these pieces. So let's add some minor code where it makes sense to not go the Book3S_64 code paths and add compat defines on others. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17KVM: PPC: Book3S_32 guest MMU fixesAlexander Graf1-7/+23
This patch makes the VSID of mapped pages always reflecting all special cases we have, like split mode. It also changes the tlbie mask to 0x0ffff000 according to the spec. The mask we used before was incorrect. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25KVM: PPC: Fix typo in book3s_32 debug codeAlexander Graf1-1/+1
There's a typo in the debug ifdef of the book3s_32 mmu emulation. While trying to debug something I stumbled across that and wanted to save anyone after me (or myself later) from having to debug that again. So let's fix the ifdef. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-11-05Add book3s_32 guest MMUAlexander Graf1-0/+372
This patch adds an implementation for a G3/G4 MMU, so we can run G3 and G4 guests in KVM on Book3s_64. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>