- 09 Oct, 2018 32 commits
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Suraj Jitindar Singh authored
The hcall H_ENTER_NESTED takes two parameters: the address in L1 guest memory of a hv_regs struct and the address of a pt_regs struct. The hcall requests the L0 hypervisor to use the register values in these structs to run a L2 guest and to return the exit state of the L2 guest in these structs. These are in the endianness of the L1 guest, rather than being always big-endian as is usually the case for PAPR hypercalls. This is convenient because it means that the L1 guest can pass the address of the regs field in its kvm_vcpu_arch struct. This also improves performance slightly by avoiding the need for two copies of the pt_regs struct. When reading/writing these structures, this patch handles the case where the endianness of the L1 guest differs from that of the L0 hypervisor, by byteswapping the structures after reading and before writing them back. Since all the fields of the pt_regs are of the same type, i.e., unsigned long, we treat it as an array of unsigned longs. The fields of struct hv_guest_state are not all the same, so its fields are byteswapped individually. Reviewed-by:
David Gibson <david@gibson.dropbear.id.au> Signed-off-by:
Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by:
Paul Mackerras <paulus@ozlabs.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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Suraj Jitindar Singh authored
restore_hv_regs() is used to copy the hv_regs L1 wants to set to run the nested (L2) guest into the vcpu structure. We need to sanitise these values to ensure we don't let the L1 guest hypervisor do things we don't want it to. We don't let data address watchpoints or completed instruction address breakpoints be set to match in hypervisor state. We also don't let L1 enable features in the hypervisor facility status and control register (HFSCR) for L2 which we have disabled for L1. That is L2 will get the subset of features which the L0 hypervisor has enabled for L1 and the features L1 wants to enable for L2. This could mean we give L1 a hypervisor facility unavailable interrupt for a facility it thinks it has enabled, however it shouldn't have enabled a facility it itself doesn't have for the L2 guest. We sanitise the registers when copying in the L2 hv_regs. We don't need to sanitise when copying back the L1 hv_regs since these shouldn't be able to contain invalid values as they're just what was copied out. Reviewed-by:
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Paul Mackerras authored
This adds a one-reg register identifier which can be used to read and set the virtual PTCR for the guest. This register identifies the address and size of the virtual partition table for the guest, which contains information about the nested guests under this guest. Migrating this value is the only extra requirement for migrating a guest which has nested guests (assuming of course that the destination host supports nested virtualization in the kvm-hv module). Reviewed-by:
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Paul Mackerras authored
When running as a nested hypervisor, this avoids reading hypervisor privileged registers (specifically HFSCR, LPIDR and LPCR) at startup; instead reasonable default values are used. This also avoids writing LPIDR in the single-vcpu entry/exit path. Also, this removes the check for CPU_FTR_HVMODE in kvmppc_mmu_hv_init() since its only caller already checks this. Reviewed-by:
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Suraj Jitindar Singh authored
This is only done at level 0, since only level 0 knows which physical CPU a vcpu is running on. This does for nested guests what L0 already did for its own guests, which is to flush the TLB on a pCPU when it goes to run a vCPU there, and there is another vCPU in the same VM which previously ran on this pCPU and has now started to run on another pCPU. This is to handle the situation where the other vCPU touched a mapping, moved to another pCPU and did a tlbiel (local-only tlbie) on that new pCPU and thus left behind a stale TLB entry on this pCPU. This introduces a limit on the the vcpu_token values used in the H_ENTER_NESTED hcall -- they must now be less than NR_CPUS. [paulus@ozlabs.org - made prev_cpu array be short[] to reduce memory consumption.] Reviewed-by:
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Paul Mackerras authored
This adds code to call the H_TLB_INVALIDATE hypercall when running as a guest, in the cases where we need to invalidate TLBs (or other MMU caches) as part of managing the mappings for a nested guest. Calling H_TLB_INVALIDATE lets the nested hypervisor inform the parent hypervisor about changes to partition-scoped page tables or the partition table without needing to do hypervisor-privileged tlbie instructions. Reviewed-by:
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Suraj Jitindar Singh authored
When running a nested (L2) guest the guest (L1) hypervisor will use the H_TLB_INVALIDATE hcall when it needs to change the partition scoped page tables or the partition table which it manages. It will use this hcall in the situations where it would use a partition-scoped tlbie instruction if it were running in hypervisor mode. The H_TLB_INVALIDATE hcall can invalidate different scopes: Invalidate TLB for a given target address: - This invalidates a single L2 -> L1 pte - We need to invalidate any L2 -> L0 shadow_pgtable ptes which map the L2 address space which is being invalidated. This is because a single L2 -> L1 pte may have been mapped with more than one pte in the L2 -> L0 page tables. Invalidate the entire TLB for a given LPID or for all LPIDs: - Invalidate the entire shadow_pgtable for a given nested guest, or for all nested guests. Invalidate the PWC (page walk cache) for a given LPID or for all LPIDs: - We don't cache the PWC, so nothing to do. Invalidate the entire TLB, PWC and partition table for a given/all LPIDs: - Here we re-read the partition table entry and remove the nested state for any nested guest for which the first doubleword of the partition table entry is now zero. The H_TLB_INVALIDATE hcall takes as parameters the tlbie instruction word (of which only the RIC, PRS and R fields are used), the rS value (giving the lpid, where required) and the rB value (giving the IS, AP and EPN values). [paulus@ozlabs.org - adapted to having the partition table in guest memory, added the H_TLB_INVALIDATE implementation, removed tlbie instruction emulation, reworded the commit message.] Reviewed-by:
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Suraj Jitindar Singh authored
When a host (L0) page which is mapped into a (L1) guest is in turn mapped through to a nested (L2) guest we keep a reverse mapping (rmap) so that these mappings can be retrieved later. Whenever we create an entry in a shadow_pgtable for a nested guest we create a corresponding rmap entry and add it to the list for the L1 guest memslot at the index of the L1 guest page it maps. This means at the L1 guest memslot we end up with lists of rmaps. When we are notified of a host page being invalidated which has been mapped through to a (L1) guest, we can then walk the rmap list for that guest page, and find and invalidate all of the corresponding shadow_pgtable entries. In order to reduce memory consumption, we compress the information for each rmap entry down to 52 bits -- 12 bits for the LPID and 40 bits for the guest real page frame number -- which will fit in a single unsigned long. To avoid a scenario where a guest can trigger unbounded memory allocations, we scan the list when adding an entry to see if there is already an entry with the contents we need. This can occur, because we don't ever remove entries from the middle of a list. A struct nested guest rmap is a list pointer and an rmap entry; ---------------- | next pointer | ---------------- | rmap entry | ---------------- Thus the rmap pointer for each guest frame number in the memslot can be either NULL, a single entry, or a pointer to a list of nested rmap entries. gfn memslot rmap array ------------------------- 0 | NULL | (no rmap entry) ------------------------- 1 | single rmap entry | (rmap entry with low bit set) ------------------------- 2 | list head pointer | (list of rmap entries) ------------------------- The final entry always has the lowest bit set and is stored in the next pointer of the last list entry, or as a single rmap entry. With a list of rmap entries looking like; ----------------- ----------------- ------------------------- | list head ptr | ----> | next pointer | ----> | single rmap entry | ----------------- ----------------- ------------------------- | rmap entry | | rmap entry | ----------------- ------------------------- Signed-off-by:
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Suraj Jitindar Singh authored
Consider a normal (L1) guest running under the main hypervisor (L0), and then a nested guest (L2) running under the L1 guest which is acting as a nested hypervisor. L0 has page tables to map the address space for L1 providing the translation from L1 real address -> L0 real address; L1 | | (L1 -> L0) | ----> L0 There are also page tables in L1 used to map the address space for L2 providing the translation from L2 real address -> L1 read address. Since the hardware can only walk a single level of page table, we need to maintain in L0 a "shadow_pgtable" for L2 which provides the translation from L2 real address -> L0 real address. Which looks like; L2 L2 | | | (L2 -> L1) | | | ----> L1 | (L2 -> L0) | | | (L1 -> L0) | | | ----> L0 --------> L0 When a page fault occurs while running a nested (L2) guest we need to insert a pte into this "shadow_pgtable" for the L2 -> L0 mapping. To do this we need to: 1. Walk the pgtable in L1 memory to find the L2 -> L1 mapping, and provide a page fault to L1 if this mapping doesn't exist. 2. Use our L1 -> L0 pgtable to convert this L1 address to an L0 address, or try to insert a pte for that mapping if it doesn't exist. 3. Now we have a L2 -> L0 mapping, insert this into our shadow_pgtable Once this mapping exists we can take rc faults when hardware is unable to automatically set the reference and change bits in the pte. On these we need to: 1. Check the rc bits on the L2 -> L1 pte match, and otherwise reflect the fault down to L1. 2. Set the rc bits in the L1 -> L0 pte which corresponds to the same host page. 3. Set the rc bits in the L2 -> L0 pte. As we reuse a large number of functions in book3s_64_mmu_radix.c for this we also needed to refactor a number of these functions to take an lpid parameter so that the correct lpid is used for tlb invalidations. The functionality however has remained the same. Reviewed-by:
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Paul Mackerras authored
When we are running as a nested hypervisor, we use a hypercall to enter the guest rather than code in book3s_hv_rmhandlers.S. This means that the hypercall handlers listed in hcall_real_table never get called. There are some hypercalls that are handled there and not in kvmppc_pseries_do_hcall(), which therefore won't get processed for a nested guest. To fix this, we add cases to kvmppc_pseries_do_hcall() to handle those hypercalls, with the following exceptions: - The HPT hypercalls (H_ENTER, H_REMOVE, etc.) are not handled because we only support radix mode for nested guests. - H_CEDE has to be handled specially because the cede logic in kvmhv_run_single_vcpu assumes that it has been processed by the time that kvmhv_p9_guest_entry() returns. Therefore we put a special case for H_CEDE in kvmhv_p9_guest_entry(). For the XICS hypercalls, if real-mode processing is enabled, then the virtual-mode handlers assume that they are being called only to finish up the operation. Therefore we turn off the real-mode flag in the XICS code when running as a nested hypervisor. Reviewed-by:
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Paul Mackerras authored
This adds code to call the H_IPI and H_EOI hypercalls when we are running as a nested hypervisor (i.e. without the CPU_FTR_HVMODE cpu feature) and we would otherwise access the XICS interrupt controller directly or via an OPAL call. Reviewed-by:
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Paul Mackerras authored
This adds a new hypercall, H_ENTER_NESTED, which is used by a nested hypervisor to enter one of its nested guests. The hypercall supplies register values in two structs. Those values are copied by the level 0 (L0) hypervisor (the one which is running in hypervisor mode) into the vcpu struct of the L1 guest, and then the guest is run until an interrupt or error occurs which needs to be reported to L1 via the hypercall return value. Currently this assumes that the L0 and L1 hypervisors are the same endianness, and the structs passed as arguments are in native endianness. If they are of different endianness, the version number check will fail and the hcall will be rejected. Nested hypervisors do not support indep_threads_mode=N, so this adds code to print a warning message if the administrator has set indep_threads_mode=N, and treat it as Y. Reviewed-by:
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Paul Mackerras authored
This starts the process of adding the code to support nested HV-style virtualization. It defines a new H_SET_PARTITION_TABLE hypercall which a nested hypervisor can use to set the base address and size of a partition table in its memory (analogous to the PTCR register). On the host (level 0 hypervisor) side, the H_SET_PARTITION_TABLE hypercall from the guest is handled by code that saves the virtual PTCR value for the guest. This also adds code for creating and destroying nested guests and for reading the partition table entry for a nested guest from L1 memory. Each nested guest has its own shadow LPID value, different in general from the LPID value used by the nested hypervisor to refer to it. The shadow LPID value is allocated at nested guest creation time. Nested hypervisor functionality is only available for a radix guest, which therefore means a radix host on a POWER9 (or later) processor. Signed-off-by:
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Paul Mackerras authored
kvmppc_unmap_pte() does a sequence of operations that are open-coded in kvm_unmap_radix(). This extends kvmppc_unmap_pte() a little so that it can be used by kvm_unmap_radix(), and makes kvm_unmap_radix() call it. Reviewed-by:
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Suraj Jitindar Singh authored
The radix page fault handler accounts for all cases, including just needing to insert a pte. This breaks it up into separate functions for the two main cases; setting rc and inserting a pte. This allows us to make the setting of rc and inserting of a pte generic for any pgtable, not specific to the one for this guest. [paulus@ozlabs.org - reduced diffs from previous code] Reviewed-by:
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Suraj Jitindar Singh authored
kvmppc_mmu_radix_xlate() is used to translate an effective address through the process tables. The process table and partition tables have identical layout. Exploit this fact to make the kvmppc_mmu_radix_xlate() function able to translate either an effective address through the process tables or a guest real address through the partition tables. [paulus@ozlabs.org - reduced diffs from previous code] Reviewed-by:
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Suraj Jitindar Singh authored
When destroying a VM we return the LPID to the pool, however we never zero the partition table entry. This is instead done when we reallocate the LPID. Zero the partition table entry on VM teardown before returning the LPID to the pool. This means if we were running as a nested hypervisor the real hypervisor could use this to determine when it can free resources. Reviewed-by:
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Paul Mackerras authored
When the 'regs' field was added to struct kvm_vcpu_arch, the code was changed to use several of the fields inside regs (e.g., gpr, lr, etc.) but not the ccr field, because the ccr field in struct pt_regs is 64 bits on 64-bit platforms, but the cr field in kvm_vcpu_arch is only 32 bits. This changes the code to use the regs.ccr field instead of cr, and changes the assembly code on 64-bit platforms to use 64-bit loads and stores instead of 32-bit ones. Reviewed-by:
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Paul Mackerras authored
This adds a file called 'radix' in the debugfs directory for the guest, which when read gives all of the valid leaf PTEs in the partition-scoped radix tree for a radix guest, in human-readable format. It is analogous to the existing 'htab' file which dumps the HPT entries for a HPT guest. Reviewed-by:
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Paul Mackerras authored
Currently the code for handling hypervisor instruction page faults passes 0 for the flags indicating the type of fault, which is OK in the usual case that the page is not mapped in the partition-scoped page tables. However, there are other causes for hypervisor instruction page faults, such as not being to update a reference (R) or change (C) bit. The cause is indicated in bits in HSRR1, including a bit which indicates that the fault is due to not being able to write to a page (for example to update an R or C bit). Not handling these other kinds of faults correctly can lead to a loop of continual faults without forward progress in the guest. In order to handle these faults better, this patch constructs a "DSISR-like" value from the bits which DSISR and SRR1 (for a HISI) have in common, and passes it to kvmppc_book3s_hv_page_fault() so that it knows what caused the fault. Reviewed-by:
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Paul Mackerras authored
This creates an alternative guest entry/exit path which is used for radix guests on POWER9 systems when we have indep_threads_mode=Y. In these circumstances there is exactly one vcpu per vcore and there is no coordination required between vcpus or vcores; the vcpu can enter the guest without needing to synchronize with anything else. The new fast path is implemented almost entirely in C in book3s_hv.c and runs with the MMU on until the guest is entered. On guest exit we use the existing path until the point where we are committed to exiting the guest (as distinct from handling an interrupt in the low-level code and returning to the guest) and we have pulled the guest context from the XIVE. At that point we check a flag in the stack frame to see whether we came in via the old path and the new path; if we came in via the new path then we go back to C code to do the rest of the process of saving the guest context and restoring the host context. The C code is split into separate functions for handling the OS-accessible state and the hypervisor state, with the idea that the latter can be replaced by a hypercall when we implement nested virtualization. Signed-off-by:
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Paul Mackerras authored
Currently kvmppc_handle_exit_hv() is called with the vcore lock held because it is called within a for_each_runnable_thread loop. However, we already unlock the vcore within kvmppc_handle_exit_hv() under certain circumstances, and this is safe because (a) any vcpus that become runnable and are added to the runnable set by kvmppc_run_vcpu() have their vcpu->arch.trap == 0 and can't actually run in the guest (because the vcore state is VCORE_EXITING), and (b) for_each_runnable_thread is safe against addition or removal of vcpus from the runnable set. Therefore, in order to simplify things for following patches, let's drop the vcore lock in the for_each_runnable_thread loop, so kvmppc_handle_exit_hv() gets called without the vcore lock held. Reviewed-by:
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Paul Mackerras authored
This adds a parameter to __kvmppc_save_tm and __kvmppc_restore_tm which allows the caller to indicate whether it wants the nonvolatile register state to be preserved across the call, as required by the C calling conventions. This parameter being non-zero also causes the MSR bits that enable TM, FP, VMX and VSX to be preserved. The condition register and DSCR are now always preserved. With this, kvmppc_save_tm_hv and kvmppc_restore_tm_hv can be called from C code provided the 3rd parameter is non-zero. So that these functions can be called from modules, they now include code to set the TOC pointer (r2) on entry, as they can call other built-in C functions which will assume the TOC to have been set. Also, the fake suspend code in kvmppc_save_tm_hv is modified here to assume that treclaim in fake-suspend state does not modify any registers, which is the case on POWER9. This enables the code to be simplified quite a bit. _kvmppc_save_tm_pr and _kvmppc_restore_tm_pr become much simpler with this change, since they now only need to save and restore TAR and pass 1 for the 3rd argument to __kvmppc_{save,restore}_tm. Reviewed-by: -
Paul Mackerras authored
This streamlines the first part of the code that handles a hypervisor interrupt that occurred in the guest. With this, all of the real-mode handling that occurs is done before the "guest_exit_cont" label; once we get to that label we are committed to exiting to host virtual mode. Thus the machine check and HMI real-mode handling is moved before that label. Also, the code to handle external interrupts is moved out of line, as is the code that calls kvmppc_realmode_hmi_handler(). Signed-off-by:
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Paul Mackerras authored
This pulls out the assembler code that is responsible for saving and restoring the PMU state for the host and guest into separate functions so they can be used from an alternate entry path. The calling convention is made compatible with C. Reviewed-by:
Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Signed-off-by:
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Paul Mackerras authored
This is based on a patch by Suraj Jitindar Singh. This moves the code in book3s_hv_rmhandlers.S that generates an external, decrementer or privileged doorbell interrupt just before entering the guest to C code in book3s_hv_builtin.c. This is to make future maintenance and modification easier. The algorithm expressed in the C code is almost identical to the previous algorithm. Reviewed-by:
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Paul Mackerras authored
This removes code that clears the external interrupt pending bit in the pending_exceptions bitmap. This is left over from an earlier iteration of the code where this bit was set when an escalation interrupt arrived in order to wake the vcpu from cede. Currently we set the vcpu->arch.irq_pending flag instead for this purpose. Therefore there is no need to do anything with the pending_exceptions bitmap. Reviewed-by:
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Paul Mackerras authored
Currently we use two bits in the vcpu pending_exceptions bitmap to indicate that an external interrupt is pending for the guest, one for "one-shot" interrupts that are cleared when delivered, and one for interrupts that persist until cleared by an explicit action of the OS (e.g. an acknowledge to an interrupt controller). The BOOK3S_IRQPRIO_EXTERNAL bit is used for one-shot interrupt requests and BOOK3S_IRQPRIO_EXTERNAL_LEVEL is used for persisting interrupts. In practice BOOK3S_IRQPRIO_EXTERNAL never gets used, because our Book3S platforms generally, and pseries in particular, expect external interrupt requests to persist until they are acknowledged at the interrupt controller. That combined with the confusion introduced by having two bits for what is essentially the same thing makes it attractive to simplify things by only using one bit. This patch does that. With this patch there is only BOOK3S_IRQPRIO_EXTERNAL, and by default it has the semantics of a persisting interrupt. In order to avoid breaking the ABI, we introduce a new "external_oneshot" flag which preserves the behaviour of the KVM_INTERRUPT ioctl with the KVM_INTERRUPT_SET argument. Reviewed-by:
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Paul Mackerras authored
When doing nested virtualization, it is only necessary to do the transactional memory hypervisor assist at level 0, that is, when we are in hypervisor mode. Nested hypervisors can just use the TM facilities as architected. Therefore we should clear the CPU_FTR_P9_TM_HV_ASSIST bit when we are not in hypervisor mode, along with the CPU_FTR_HVMODE bit. Doing this will not change anything at this stage because the only code that tests CPU_FTR_P9_TM_HV_ASSIST is in HV KVM, which currently can only be used when when CPU_FTR_HVMODE is set. Reviewed-by:
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Alexey Kardashevskiy authored
The kvmppc_gpa_to_ua() helper itself takes care of the permission bits in the TCE and yet every single caller removes them. This changes semantics of kvmppc_gpa_to_ua() so it takes TCEs (which are GPAs + TCE permission bits) to make the callers simpler. This should cause no behavioural change. Signed-off-by:
Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by:
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Alexey Kardashevskiy authored
At the moment if the PUT_TCE{_INDIRECT} handlers fail to update the hardware tables, we print a warning once, clear the entry and continue. This is so as at the time the assumption was that if a VFIO device is hotplugged into the guest, and the userspace replays virtual DMA mappings (i.e. TCEs) to the hardware tables and if this fails, then there is nothing useful we can do about it. However the assumption is not valid as these handlers are not called for TCE replay (VFIO ioctl interface is used for that) and these handlers are for new TCEs. This returns an error to the guest if there is a request which cannot be processed. By now the only possible failure must be H_TOO_HARD. Signed-off-by: -
Alexey Kardashevskiy authored
The userspace can request an arbitrary supported page size for a DMA window and this works fine as long as the mapped memory is backed with the pages of the same or bigger size; if this is not the case, mm_iommu_ua_to_hpa{_rm}() fail and tables do not populated with dangerously incorrect TCEs. However since it is quite easy to misconfigure the KVM and we do not do reverts to all changes made to TCE tables if an error happens in a middle, we better do the acceptable page size validation before we even touch the tables. This enhances kvmppc_tce_validate() to check the hardware IOMMU page sizes against the preregistered memory page sizes. Since the new check uses real/virtual mode helpers, this renames kvmppc_tce_validate() to kvmppc_rm_tce_validate() to handle the real mode case and mirrors it for the virtual mode under the old name. The real mode handler is not used for the virtual mode as: 1. it uses _lockless() list traversing primitives instead of RCU; 2. realmode's mm_iommu_ua_to_hpa_rm() uses vmalloc_to_phys() which virtual mode does not have to use and since on POWER9+radix only virtual mode handlers actually work, we do not want to slow down that path even a bit. This removes EXPORT_SYMBOL_GPL(kvmppc_tce_validate) as the validators are static now. From now on the attempts on mapping IOMMU pages bigger than allowed will result in KVM exit. Signed-off-by:
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- 02 Oct, 2018 3 commits
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Alexey Kardashevskiy authored
We return H_TOO_HARD from TCE update handlers when we think that the next handler (realmode -> virtual mode -> user mode) has a chance to handle the request; H_HARDWARE/H_CLOSED otherwise. This changes the handlers to return H_TOO_HARD on every error giving the userspace an opportunity to handle any request or at least log them all. Signed-off-by:
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Alexey Kardashevskiy authored
The KVM TCE handlers are written in a way so they fail when either something went horribly wrong or the userspace did some obvious mistake such as passing a misaligned address. We are going to enhance the TCE checker to fail on attempts to map bigger IOMMU page than the underlying pinned memory so let's valitate TCE beforehand. This should cause no behavioral change. Signed-off-by:
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Michael Ellerman authored
Some commits we'd like to share between the powerpc and kvm-ppc tree for next have dependencies on commits that went into 4.19 via the kvm-ppc-fixes branch and weren't merged before 4.19-rc3, which is our base commit. So merge the kvm-ppc-fixes branch into topic/ppc-kvm.
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- 11 Sep, 2018 2 commits
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Nicholas Piggin authored
THP paths can defer splitting compound pages until after the actual remap and TLB flushes to split a huge PMD/PUD. This causes radix partition scope page table mappings to get out of synch with the host qemu page table mappings. This results in random memory corruption in the guest when running with THP. The easiest way to reproduce is use KVM balloon to free up a lot of memory in the guest and then shrink the balloon to give the memory back, while some work is being done in the guest. Cc: David Gibson <david@gibson.dropbear.id.au> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: kvm-ppc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Alexey Kardashevskiy authored
At the moment the real mode handler of H_PUT_TCE calls iommu_tce_xchg_rm() which in turn reads the old TCE and if it was a valid entry, marks the physical page dirty if it was mapped for writing. Since it is in real mode, realmode_pfn_to_page() is used instead of pfn_to_page() to get the page struct. However SetPageDirty() itself reads the compound page head and returns a virtual address for the head page struct and setting dirty bit for that kills the system. This adds additional dirty bit tracking into the MM/IOMMU API for use in the real mode. Note that this does not change how VFIO and KVM (in virtual mode) set this bit. The KVM (real mode) changes include: - use the lowest bit of the cached host phys address to carry the dirty bit; - mark pages dirty when they are unpinned which happens when the preregistered memory is released which always happens in virtual mode; - add mm_iommu_ua_mark_dirty_rm() helper to set delayed dirty bit; - change iommu_tce_xchg_rm() to take the kvm struct for the mm to use in the new mm_iommu_ua_mark_dirty_rm() helper; - move iommu_tce_xchg_rm() to book3s_64_vio_hv.c (which is the only caller anyway) to reduce the real mode KVM and IOMMU knowledge across different subsystems. This removes realmode_pfn_to_page() as it is not used anymore. While we at it, remove some EXPORT_SYMBOL_GPL() as that code is for the real mode only and modules cannot call it anyway. Signed-off-by:
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- 10 Sep, 2018 1 commit
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Linus Torvalds authored
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- 09 Sep, 2018 2 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A set of fixes for x86: - Prevent multiplication result truncation on 32bit. Introduced with the early timestamp reworrk. - Ensure microcode revision storage to be consistent under all circumstances - Prevent write tearing of PTEs - Prevent confusion of user and kernel reegisters when dumping fatal signals verbosely - Make an error return value in a failure path of the vector allocation negative. Returning EINVAL might the caller assume success and causes further wreckage. - A trivial kernel doc warning fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Use WRITE_ONCE() when setting PTEs x86/apic/vector: Make error return value negative x86/process: Don't mix user/kernel regs in 64bit __show_regs() x86/tsc: Prevent result truncation on 32bit x86: Fix kernel-doc atomic.h warnings x86/microcode: Update the new microcode revision unconditionally x86/microcode: Make sure boot_cpu_data.microcode is up-to-date -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timekeeping fixes from Thomas Gleixner: "Two fixes for timekeeping: - Revert to the previous kthread based update, which is unfortunately required due to lock ordering issues. The removal caused boot failures on old Core2 machines. Add a proper comment why the thread needs to stay to prevent accidental removal in the future. - Fix a silly typo in a function declaration" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clocksource: Revert "Remove kthread" timekeeping: Fix declaration of read_persistent_wall_and_boot_offset()
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