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2018-01-08arm64: KVM: Use per-CPU vector when BP hardening is enabledMarc Zyngier
Now that we have per-CPU vectors, let's plug then in the KVM/arm64 code. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2017-12-22arm64: allow ID map to be extended to 52 bitsKristina Martsenko
Currently, when using VA_BITS < 48, if the ID map text happens to be placed in physical memory above VA_BITS, we increase the VA size (up to 48) and create a new table level, in order to map in the ID map text. This is okay because the system always supports 48 bits of VA. This patch extends the code such that if the system supports 52 bits of VA, and the ID map text is placed that high up, then we increase the VA size accordingly, up to 52. One difference from the current implementation is that so far the condition of VA_BITS < 48 has meant that the top level table is always "full", with the maximum number of entries, and an extra table level is always needed. Now, when VA_BITS = 48 (and using 64k pages), the top level table is not full, and we simply need to increase the number of entries in it, instead of creating a new table level. Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Bob Picco <bob.picco@oracle.com> Reviewed-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> [catalin.marinas@arm.com: reduce arguments to __create_hyp_mappings()] [catalin.marinas@arm.com: reworked/renamed __cpu_uses_extended_idmap_level()] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2017-12-22arm64: handle 52-bit addresses in TTBRKristina Martsenko
The top 4 bits of a 52-bit physical address are positioned at bits 2..5 in the TTBR registers. Introduce a couple of macros to move the bits there, and change all TTBR writers to use them. Leave TTBR0 PAN code unchanged, to avoid complicating it. A system with 52-bit PA will have PAN anyway (because it's ARMv8.1 or later), and a system without 52-bit PA can only use up to 48-bit PAs. A later patch in this series will add a kconfig dependency to ensure PAN is configured. In addition, when using 52-bit PA there is a special alignment requirement on the top-level table. We don't currently have any VA_BITS configuration that would violate the requirement, but one could be added in the future, so add a compile-time BUG_ON to check for it. Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Bob Picco <bob.picco@oracle.com> Reviewed-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> [catalin.marinas@arm.com: added TTBR_BADD_MASK_52 comment] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2017-04-09arm/arm64: KVM: Remove kvm_get_idmap_startMarc Zyngier
With __cpu_reset_hyp_mode having become fairly dumb, there is no need for kvm_get_idmap_start anymore. Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-01-30arm/arm64: KVM: Stop propagating cacheability status of a faulted pageMarc Zyngier
Now that we unconditionally flush newly mapped pages to the PoC, there is no need to care about the "uncached" status of individual pages - they must all be visible all the way down. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2017-01-30arm/arm64: KVM: Enforce unconditional flush to PoC when mapping to stage-2Marc Zyngier
When we fault in a page, we flush it to the PoC (Point of Coherency) if the faulting vcpu has its own caches off, so that it can observe the page we just brought it. But if the vcpu has its caches on, we skip that step. Bad things happen when *another* vcpu tries to access that page with its own caches disabled. At that point, there is no garantee that the data has made it to the PoC, and we access stale data. The obvious fix is to always flush to PoC when a page is faulted in, no matter what the state of the vcpu is. Cc: stable@vger.kernel.org Fixes: 2d58b733c876 ("arm64: KVM: force cache clean on page fault when caches are off") Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-09-08arm/kvm: excise redundant cache maintenanceMark Rutland
When modifying Stage-2 page tables, we perform cache maintenance to account for non-coherent page table walks. However, this is unnecessary, as page table walks are guaranteed to be coherent in the presence of the virtualization extensions. Per ARM DDI 0406C.c, section B1.7 ("The Virtualization Extensions"), the virtualization extensions mandate the multiprocessing extensions. Per ARM DDI 0406C.c, section B3.10.1 ("General TLB maintenance requirements"), as described in the sub-section titled "TLB maintenance operations and the memory order model", this maintenance is not required in the presence of the multiprocessing extensions. Hence, we need not perform this cache maintenance when modifying Stage-2 entries. This patch removes the logic for performing the redundant maintenance. To ensure visibility and ordering of updates, a dsb(ishst) that was otherwise implicit in the maintenance is folded into kvm_set_pmd() and kvm_set_pte(). Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-07-03arm/arm64: Get rid of KERN_TO_HYPMarc Zyngier
We have both KERN_TO_HYP and kern_hyp_va, which do the exact same thing. Let's standardize on the latter. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-07-03arm/arm64: KVM: Prune unused #definesMarc Zyngier
We can now remove a number of dead #defines, thanks to the trampoline code being gone. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-07-03arm/arm64: KVM: Kill free_boot_hyp_pgdMarc Zyngier
There is no way to free the boot PGD, because it doesn't exist anymore as a standalone entity. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-07-03arm/arm64: KVM: Drop boot_pgdMarc Zyngier
Since we now only have one set of page tables, the concept of boot_pgd is useless and can be removed. We still keep it as an element of the "extended idmap" thing. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-06-29arm/arm64: KVM: Add a protection parameter to create_hyp_mappingsMarc Zyngier
Currently, create_hyp_mappings applies a "one size fits all" page protection (PAGE_HYP). As we're heading towards separate protections for different sections, let's make this protection a parameter, and let the callers pass their prefered protection (PAGE_HYP for everyone for the time being). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-05-19Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Paolo Bonzini: "Small release overall. x86: - miscellaneous fixes - AVIC support (local APIC virtualization, AMD version) s390: - polling for interrupts after a VCPU goes to halted state is now enabled for s390 - use hardware provided information about facility bits that do not need any hypervisor activity, and other fixes for cpu models and facilities - improve perf output - floating interrupt controller improvements. MIPS: - miscellaneous fixes PPC: - bugfixes only ARM: - 16K page size support - generic firmware probing layer for timer and GIC Christoffer Dall (KVM-ARM maintainer) says: "There are a few changes in this pull request touching things outside KVM, but they should all carry the necessary acks and it made the merge process much easier to do it this way." though actually the irqchip maintainers' acks didn't make it into the patches. Marc Zyngier, who is both irqchip and KVM-ARM maintainer, later acked at http://mid.gmane.org/573351D1.4060303@arm.com ('more formally and for documentation purposes')" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (82 commits) KVM: MTRR: remove MSR 0x2f8 KVM: x86: make hwapic_isr_update and hwapic_irr_update look the same svm: Manage vcpu load/unload when enable AVIC svm: Do not intercept CR8 when enable AVIC svm: Do not expose x2APIC when enable AVIC KVM: x86: Introducing kvm_x86_ops.apicv_post_state_restore svm: Add VMEXIT handlers for AVIC svm: Add interrupt injection via AVIC KVM: x86: Detect and Initialize AVIC support svm: Introduce new AVIC VMCB registers KVM: split kvm_vcpu_wake_up from kvm_vcpu_kick KVM: x86: Introducing kvm_x86_ops VCPU blocking/unblocking hooks KVM: x86: Introducing kvm_x86_ops VM init/destroy hooks KVM: x86: Rename kvm_apic_get_reg to kvm_lapic_get_reg KVM: x86: Misc LAPIC changes to expose helper functions KVM: shrink halt polling even more for invalid wakeups KVM: s390: set halt polling to 80 microseconds KVM: halt_polling: provide a way to qualify wakeups during poll KVM: PPC: Book3S HV: Re-enable XICS fast path for irqfd-generated interrupts kvm: Conditionally register IRQ bypass consumer ...
2016-05-09kvm: arm64: Enable hardware updates of the Access Flag for Stage 2 page tablesCatalin Marinas
The ARMv8.1 architecture extensions introduce support for hardware updates of the access and dirty information in page table entries. With VTCR_EL2.HA enabled (bit 21), when the CPU accesses an IPA with the PTE_AF bit cleared in the stage 2 page table, instead of raising an Access Flag fault to EL2 the CPU sets the actual page table entry bit (10). To ensure that kernel modifications to the page table do not inadvertently revert a bit set by hardware updates, certain Stage 2 software pte/pmd operations must be performed atomically. The main user of the AF bit is the kvm_age_hva() mechanism. The kvm_age_hva_handler() function performs a "test and clear young" action on the pte/pmd. This needs to be atomic in respect of automatic hardware updates of the AF bit. Since the AF bit is in the same position for both Stage 1 and Stage 2, the patch reuses the existing ptep_test_and_clear_young() functionality if __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG is defined. Otherwise, the existing pte_young/pte_mkold mechanism is preserved. The kvm_set_s2pte_readonly() (and the corresponding pmd equivalent) have to perform atomic modifications in order to avoid a race with updates of the AF bit. The arm64 implementation has been re-written using exclusives. Currently, kvm_set_s2pte_writable() (and pmd equivalent) take a pointer argument and modify the pte/pmd in place. However, these functions are only used on local variables rather than actual page table entries, so it makes more sense to follow the pte_mkwrite() approach for stage 1 attributes. The change to kvm_s2pte_mkwrite() makes it clear that these functions do not modify the actual page table entries. The (pte|pmd)_mkyoung() uses on Stage 2 entries (setting the AF bit explicitly) do not need to be modified since hardware updates of the dirty status are not supported by KVM, so there is no possibility of losing such information. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-04-28arm64: kvm: allows kvm cpu hotplugAKASHI Takahiro
The current kvm implementation on arm64 does cpu-specific initialization at system boot, and has no way to gracefully shutdown a core in terms of kvm. This prevents kexec from rebooting the system at EL2. This patch adds a cpu tear-down function and also puts an existing cpu-init code into a separate function, kvm_arch_hardware_disable() and kvm_arch_hardware_enable() respectively. We don't need the arm64 specific cpu hotplug hook any more. Since this patch modifies common code between arm and arm64, one stub definition, __cpu_reset_hyp_mode(), is added on arm side to avoid compilation errors. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> [Rebase, added separate VHE init/exit path, changed resets use of kvm_call_hyp() to the __version, en/disabled hardware in init_subsystems(), added icache maintenance to __kvm_hyp_reset() and removed lr restore, removed guest-enter after teardown handling] Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-21kvm-arm: Cleanup stage2 pgd handlingSuzuki K Poulose
Now that we don't have any fake page table levels for arm64, cleanup the common code to get rid of the dead code. Cc: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
2016-04-21kvm-arm: Cleanup kvm_* wrappersSuzuki K Poulose
Now that we have switched to explicit page table routines, get rid of the obsolete kvm_* wrappers. Also, kvm_tlb_flush_vmid_by_ipa is now called only on stage2 page tables, hence get rid of the redundant check. Cc: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
2016-04-21kvm-arm: arm: Introduce hyp page table empty checksSuzuki K Poulose
Introduce hyp_pxx_table_empty helpers for checking whether a given table entry is empty. This will be used explicitly once we switch to explicit routines for hyp page table walk. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-04-21kvm-arm: arm32: Introduce stage2 page table helpersSuzuki K Poulose
Define the page table helpers for walking the stage2 pagetable for arm. Since both hyp and stage2 have the same number of levels, as that of the host we reuse the host helpers. The exceptions are the p.d_addr_end routines which have to deal with IPA > 32bit, hence we use the open coded version of their host helpers which supports 64bit. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-04-21kvm arm: Move fake PGD handling to arch specific filesSuzuki K Poulose
Rearrange the code for fake pgd handling, which is applicable only for arm64. This will later be removed once we introduce the stage2 page table walker macros. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
2016-02-29ARM: KVM: Move CP15 array into the CPU context structureMarc Zyngier
Continuing our rework of the CPU context, we now move the CP15 array into the CPU context structure. As this causes quite a bit of churn, we introduce the vcpu_cp15() macro that abstract the location of the actual array. This will probably help next time we have to revisit that code. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.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>
2015-12-18arm64: KVM: Add support for 16-bit VMIDVladimir Murzin
The ARMv8.1 architecture extension allows to choose between 8-bit and 16-bit of VMID, so use this capability for KVM. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-04-16Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Will Deacon: "Here are the core arm64 updates for 4.1. Highlights include a significant rework to head.S (allowing us to boot on machines with physical memory at a really high address), an AES performance boost on Cortex-A57 and the ability to run a 32-bit userspace with 64k pages (although this requires said userspace to be built with a recent binutils). The head.S rework spilt over into KVM, so there are some changes under arch/arm/ which have been acked by Marc Zyngier (KVM co-maintainer). In particular, the linker script changes caused us some issues in -next, so there are a few merge commits where we had to apply fixes on top of a stable branch. Other changes include: - AES performance boost for Cortex-A57 - AArch32 (compat) userspace with 64k pages - Cortex-A53 erratum workaround for #845719 - defconfig updates (new platforms, PCI, ...)" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (39 commits) arm64: fix midr range for Cortex-A57 erratum 832075 arm64: errata: add workaround for cortex-a53 erratum #845719 arm64: Use bool function return values of true/false not 1/0 arm64: defconfig: updates for 4.1 arm64: Extract feature parsing code from cpu_errata.c arm64: alternative: Allow immediate branch as alternative instruction arm64: insn: Add aarch64_insn_decode_immediate ARM: kvm: round HYP section to page size instead of log2 upper bound ARM: kvm: assert on HYP section boundaries not actual code size arm64: head.S: ensure idmap_t0sz is visible arm64: pmu: add support for interrupt-affinity property dt: pmu: extend ARM PMU binding to allow for explicit interrupt affinity arm64: head.S: ensure visibility of page tables arm64: KVM: use ID map with increased VA range if required arm64: mm: increase VA range of identity map ARM: kvm: implement replacement for ld's LOG2CEIL() arm64: proc: remove unused cpu_get_pgd macro arm64: enforce x1|x2|x3 == 0 upon kernel entry as per boot protocol arm64: remove __calc_phys_offset arm64: merge __enable_mmu and __turn_mmu_on ...
2015-03-23arm64: KVM: use ID map with increased VA range if requiredArd Biesheuvel
This patch modifies the HYP init code so it can deal with system RAM residing at an offset which exceeds the reach of VA_BITS. Like for EL1, this involves configuring an additional level of translation for the ID map. However, in case of EL2, this implies that all translations use the extra level, as we cannot seamlessly switch between translation tables with different numbers of translation levels. So add an extra translation table at the root level. Since the ID map and the runtime HYP map are guaranteed not to overlap, they can share this root level, and we can essentially merge these two tables into one. Tested-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-11arm64: KVM: Do not use pgd_index to index stage-2 pgdMarc Zyngier
The kernel's pgd_index macro is designed to index a normal, page sized array. KVM is a bit diffferent, as we can use concatenated pages to have a bigger address space (for example 40bit IPA with 4kB pages gives us an 8kB PGD. In the above case, the use of pgd_index will always return an index inside the first 4kB, which makes a guest that has memory above 0x8000000000 rather unhappy, as it spins forever in a page fault, whist the host happilly corrupts the lower pgd. The obvious fix is to get our own kvm_pgd_index that does the right thing(tm). Tested on X-Gene with a hacked kvmtool that put memory at a stupidly high address. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-03-11arm64: KVM: Fix stage-2 PGD allocation to have per-page refcountingMarc Zyngier
We're using __get_free_pages with to allocate the guest's stage-2 PGD. The standard behaviour of this function is to return a set of pages where only the head page has a valid refcount. This behaviour gets us into trouble when we're trying to increment the refcount on a non-head page: page:ffff7c00cfb693c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000000() page dumped because: VM_BUG_ON_PAGE((*({ __attribute__((unused)) typeof((&page->_count)->counter) __var = ( typeof((&page->_count)->counter)) 0; (volatile typeof((&page->_count)->counter) *)&((&page->_count)->counter); })) <= 0) BUG: failure at include/linux/mm.h:548/get_page()! Kernel panic - not syncing: BUG! CPU: 1 PID: 1695 Comm: kvm-vcpu-0 Not tainted 4.0.0-rc1+ #3825 Hardware name: APM X-Gene Mustang board (DT) Call trace: [<ffff80000008a09c>] dump_backtrace+0x0/0x13c [<ffff80000008a1e8>] show_stack+0x10/0x1c [<ffff800000691da8>] dump_stack+0x74/0x94 [<ffff800000690d78>] panic+0x100/0x240 [<ffff8000000a0bc4>] stage2_get_pmd+0x17c/0x2bc [<ffff8000000a1dc4>] kvm_handle_guest_abort+0x4b4/0x6b0 [<ffff8000000a420c>] handle_exit+0x58/0x180 [<ffff80000009e7a4>] kvm_arch_vcpu_ioctl_run+0x114/0x45c [<ffff800000099df4>] kvm_vcpu_ioctl+0x2e0/0x754 [<ffff8000001c0a18>] do_vfs_ioctl+0x424/0x5c8 [<ffff8000001c0bfc>] SyS_ioctl+0x40/0x78 CPU0: stopping A possible approach for this is to split the compound page using split_page() at allocation time, and change the teardown path to free one page at a time. It turns out that alloc_pages_exact() and free_pages_exact() does exactly that. While we're at it, the PGD allocation code is reworked to reduce duplication. This has been tested on an X-Gene platform with a 4kB/48bit-VA host kernel, and kvmtool hacked to place memory in the second page of the hardware PGD (PUD for the host kernel). Also regression-tested on a Cubietruck (Cortex-A7). [ Reworked to use alloc_pages_exact() and free_pages_exact() and to return pointers directly instead of by reference as arguments - Christoffer ] Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-02-23ARM: KVM: Fix size check in __coherent_cache_guest_pageJan Kiszka
The check is supposed to catch page-unaligned sizes, not the inverse. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-02-13Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM update from Paolo Bonzini: "Fairly small update, but there are some interesting new features. Common: Optional support for adding a small amount of polling on each HLT instruction executed in the guest (or equivalent for other architectures). This can improve latency up to 50% on some scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests). This also has to be enabled manually for now, but the plan is to auto-tune this in the future. ARM/ARM64: The highlights are support for GICv3 emulation and dirty page tracking s390: Several optimizations and bugfixes. Also a first: a feature exposed by KVM (UUID and long guest name in /proc/sysinfo) before it is available in IBM's hypervisor! :) MIPS: Bugfixes. x86: Support for PML (page modification logging, a new feature in Broadwell Xeons that speeds up dirty page tracking), nested virtualization improvements (nested APICv---a nice optimization), usual round of emulation fixes. There is also a new option to reduce latency of the TSC deadline timer in the guest; this needs to be tuned manually. Some commits are common between this pull and Catalin's; I see you have already included his tree. Powerpc: Nothing yet. The KVM/PPC changes will come in through the PPC maintainers, because I haven't received them yet and I might end up being offline for some part of next week" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits) KVM: ia64: drop kvm.h from installed user headers KVM: x86: fix build with !CONFIG_SMP KVM: x86: emulate: correct page fault error code for NoWrite instructions KVM: Disable compat ioctl for s390 KVM: s390: add cpu model support KVM: s390: use facilities and cpu_id per KVM KVM: s390/CPACF: Choose crypto control block format s390/kernel: Update /proc/sysinfo file with Extended Name and UUID KVM: s390: reenable LPP facility KVM: s390: floating irqs: fix user triggerable endless loop kvm: add halt_poll_ns module parameter kvm: remove KVM_MMIO_SIZE KVM: MIPS: Don't leak FPU/DSP to guest KVM: MIPS: Disable HTW while in guest KVM: nVMX: Enable nested posted interrupt processing KVM: nVMX: Enable nested virtual interrupt delivery KVM: nVMX: Enable nested apic register virtualization KVM: nVMX: Make nested control MSRs per-cpu KVM: nVMX: Enable nested virtualize x2apic mode KVM: nVMX: Prepare for using hardware MSR bitmap ...
2015-01-29arm/arm64: KVM: Use kernel mapping to perform invalidation on page faultMarc Zyngier
When handling a fault in stage-2, we need to resync I$ and D$, just to be sure we don't leave any old cache line behind. That's very good, except that we do so using the *user* address. Under heavy load (swapping like crazy), we may end up in a situation where the page gets mapped in stage-2 while being unmapped from userspace by another CPU. At that point, the DC/IC instructions can generate a fault, which we handle with kvm->mmu_lock held. The box quickly deadlocks, user is unhappy. Instead, perform this invalidation through the kernel mapping, which is guaranteed to be present. The box is much happier, and so am I. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-29arm/arm64: KVM: Invalidate data cache on unmapMarc Zyngier
Let's assume a guest has created an uncached mapping, and written to that page. Let's also assume that the host uses a cache-coherent IO subsystem. Let's finally assume that the host is under memory pressure and starts to swap things out. Before this "uncached" page is evicted, we need to make sure we invalidate potential speculated, clean cache lines that are sitting there, or the IO subsystem is going to swap out the cached view, loosing the data that has been written directly into memory. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-29arm/arm64: KVM: Use set/way op trapping to track the state of the cachesMarc Zyngier
Trying to emulate the behaviour of set/way cache ops is fairly pointless, as there are too many ways we can end-up missing stuff. Also, there is some system caches out there that simply ignore set/way operations. So instead of trying to implement them, let's convert it to VA ops, and use them as a way to re-enable the trapping of VM ops. That way, we can detect the point when the MMU/caches are turned off, and do a full VM flush (which is what the guest was trying to do anyway). This allows a 32bit zImage to boot on the APM thingy, and will probably help bootloaders in general. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-01-16KVM: arm: Add initial dirty page locking supportMario Smarduch
Add support for initial write protection of VM memslots. This patch series assumes that huge PUDs will not be used in 2nd stage tables, which is always valid on ARMv7 Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com>
2014-12-13arm/arm64: KVM: Introduce stage2_unmap_vmChristoffer Dall
Introduce a new function to unmap user RAM regions in the stage2 page tables. This is needed on reboot (or when the guest turns off the MMU) to ensure we fault in pages again and make the dcache, RAM, and icache coherent. Using unmap_stage2_range for the whole guest physical range does not work, because that unmaps IO regions (such as the GIC) which will not be recreated or in the best case faulted in on a page-by-page basis. Call this function on secondary and subsequent calls to the KVM_ARM_VCPU_INIT ioctl so that a reset VCPU will detect the guest Stage-1 MMU is off when faulting in pages and make the caches coherent. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-11-25arm, arm64: KVM: allow forced dcache flush on page faultsLaszlo Ersek
To allow handling of incoherent memslots in a subsequent patch, this patch adds a paramater 'ipa_uncached' to cache_coherent_guest_page() so that we can instruct it to flush the page's contents to DRAM even if the guest has caching globally enabled. Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-10-14arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2Christoffer Dall
This patch adds the necessary support for all host kernel PGSIZE and VA_SPACE configuration options for both EL2 and the Stage-2 page tables. However, for 40bit and 42bit PARange systems, the architecture mandates that VTCR_EL2.SL0 is maximum 1, resulting in fewer levels of stage-2 pagge tables than levels of host kernel page tables. At the same time, systems with a PARange > 42bit, we limit the IPA range by always setting VTCR_EL2.T0SZ to 24. To solve the situation with different levels of page tables for Stage-2 translation than the host kernel page tables, we allocate a dummy PGD with pointers to our actual inital level Stage-2 page table, in order for us to reuse the kernel pgtable manipulation primitives. Reproducing all these in KVM does not look pretty and unnecessarily complicates the 32-bit side. Systems with a PARange < 40bits are not yet supported. [ I have reworked this patch from its original form submitted by Jungseok to take the architecture constraints into consideration. There were too many changes from the original patch for me to preserve the authorship. Thanks to Catalin Marinas for his help in figuring out a good solution to this challenge. I have also fixed various bugs and missing error code handling from the original patch. - Christoffer ] Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-10-10arm/arm64: KVM: add 'writable' parameter to kvm_phys_addr_ioremapArd Biesheuvel
Add support for read-only MMIO passthrough mappings by adding a 'writable' parameter to kvm_phys_addr_ioremap. For the moment, mappings will be read-write even if 'writable' is false, but once the definition of PAGE_S2_DEVICE gets changed, those mappings will be created read-only. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-09-11ARM/arm64: KVM: fix use of WnR bit in kvm_is_write_fault()Ard Biesheuvel
The ISS encoding for an exception from a Data Abort has a WnR bit[6] that indicates whether the Data Abort was caused by a read or a write instruction. While there are several fields in the encoding that are only valid if the ISV bit[24] is set, WnR is not one of them, so we can read it unconditionally. Instead of fixing both implementations of kvm_is_write_fault() in place, reimplement it just once using kvm_vcpu_dabt_iswrite(), which already does the right thing with respect to the WnR bit. Also fix up the callers to pass 'vcpu' Acked-by: Laszlo Ersek <lersek@redhat.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-07-11arm/arm64: KVM: Fix and refactor unmap_rangeChristoffer Dall
unmap_range() was utterly broken, to quote Marc, and broke in all sorts of situations. It was also quite complicated to follow and didn't follow the usual scheme of having a separate iterating function for each level of page tables. Address this by refactoring the code and introduce a pgd_clear() function. Reviewed-by: Jungseok Lee <jays.lee@samsung.com> Reviewed-by: Mario Smarduch <m.smarduch@samsung.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-03-03ARM: KVM: force cache clean on page fault when caches are offMarc Zyngier
In order for a guest with caches disabled to observe data written contained in a given page, we need to make sure that page is committed to memory, and not just hanging in the cache (as guest accesses are completely bypassing the cache until it decides to enable it). For this purpose, hook into the coherent_cache_guest_page function and flush the region if the guest SCTLR register doesn't show the MMU and caches as being enabled. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
2014-03-03arm64: KVM: flush VM pages before letting the guest enable cachesMarc Zyngier
When the guest runs with caches disabled (like in an early boot sequence, for example), all the writes are diectly going to RAM, bypassing the caches altogether. Once the MMU and caches are enabled, whatever sits in the cache becomes suddenly visible, which isn't what the guest expects. A way to avoid this potential disaster is to invalidate the cache when the MMU is being turned on. For this, we hook into the SCTLR_EL1 trapping code, and scan the stage-2 page tables, invalidating the pages/sections that have already been mapped in. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-03-03ARM: KVM: introduce kvm_p*d_addr_endMarc Zyngier
The use of p*d_addr_end with stage-2 translation is slightly dodgy, as the IPA is 40bits, while all the p*d_addr_end helpers are taking an unsigned long (arm64 is fine with that as unligned long is 64bit). The fix is to introduce 64bit clean versions of the same helpers, and use them in the stage-2 page table code. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2014-03-03arm64: KVM: force cache clean on page fault when caches are offMarc Zyngier
In order for the guest with caches off to observe data written contained in a given page, we need to make sure that page is committed to memory, and not just hanging in the cache (as guest accesses are completely bypassing the cache until it decides to enable it). For this purpose, hook into the coherent_icache_guest_page function and flush the region if the guest SCTLR_EL1 register doesn't show the MMU and caches as being enabled. The function also get renamed to coherent_cache_guest_page. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
2013-12-11arm/arm64: kvm: Use virt_to_idmap instead of virt_to_phys for idmap mappingsSantosh Shilimkar
KVM initialisation fails on architectures implementing virt_to_idmap() because virt_to_phys() on such architectures won't fetch you the correct idmap page. So update the KVM ARM code to use the virt_to_idmap() to fix the issue. Since the KVM code is shared between arm and arm64, we create kvm_virt_to_phys() and handle the redirection in respective headers. Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2013-10-17KVM: ARM: Support hugetlbfs backed huge pagesChristoffer Dall
Support huge pages in KVM/ARM and KVM/ARM64. The pud_huge checking on the unmap path may feel a bit silly as the pud_huge check is always defined to false, but the compiler should be smart about this. Note: This deals only with VMAs marked as huge which are allocated by users through hugetlbfs only. Transparent huge pages can only be detected by looking at the underlying pages (or the page tables themselves) and this patch so far simply maps these on a page-by-page level in the Stage-2 page tables. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2013-08-30ARM: KVM: Fix kvm_set_pte assignmentChristoffer Dall
THe kvm_set_pte function was actually assigning the entire struct to the structure member, which should work because the structure only has that one member, but it is still not very nice. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2013-04-28ARM: KVM: perform HYP initilization for hotplugged CPUsMarc Zyngier
Now that we have the necessary infrastructure to boot a hotplugged CPU at any point in time, wire a CPU notifier that will perform the HYP init for the incoming CPU. Note that this depends on the platform code and/or firmware to boot the incoming CPU with HYP mode enabled and return to the kernel by following the normal boot path (HYP stub installed). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
2013-04-28ARM: KVM: switch to a dual-step HYP init codeMarc Zyngier
Our HYP init code suffers from two major design issues: - it cannot support CPU hotplug, as we tear down the idmap very early - it cannot perform a TLB invalidation when switching from init to runtime mappings, as pages are manipulated from PL1 exclusively The hotplug problem mandates that we keep two sets of page tables (boot and runtime). The TLB problem mandates that we're able to transition from one PGD to another while in HYP, invalidating the TLBs in the process. To be able to do this, we need to share a page between the two page tables. A page that will have the same VA in both configurations. All we need is a VA that has the following properties: - This VA can't be used to represent a kernel mapping. - This VA will not conflict with the physical address of the kernel text The vectors page seems to satisfy this requirement: - The kernel never maps anything else there - The kernel text being copied at the beginning of the physical memory, it is unlikely to use the last 64kB (I doubt we'll ever support KVM on a system with something like 4MB of RAM, but patches are very welcome). Let's call this VA the trampoline VA. Now, we map our init page at 3 locations: - idmap in the boot pgd - trampoline VA in the boot pgd - trampoline VA in the runtime pgd The init scenario is now the following: - We jump in HYP with four parameters: boot HYP pgd, runtime HYP pgd, runtime stack, runtime vectors - Enable the MMU with the boot pgd - Jump to a target into the trampoline page (remember, this is the same physical page!) - Now switch to the runtime pgd (same VA, and still the same physical page!) - Invalidate TLBs - Set stack and vectors - Profit! (or eret, if you only care about the code). Note that we keep the boot mapping permanently (it is not strictly an idmap anymore) to allow for CPU hotplug in later patches. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
2013-04-28ARM: KVM: rework HYP page table freeingMarc Zyngier
There is no point in freeing HYP page tables differently from Stage-2. They now have the same requirements, and should be dealt with the same way. Promote unmap_stage2_range to be The One True Way, and get rid of a number of nasty bugs in the process (good thing we never actually called free_hyp_pmds before...). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
2013-04-28ARM: KVM: move to a KVM provided HYP idmapMarc Zyngier
After the HYP page table rework, it is pretty easy to let the KVM code provide its own idmap, rather than expecting the kernel to provide it. It takes actually less code to do so. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>