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* ARM: kvm: use inner-shareable barriers after TLB flushingWill Deacon2013-08-121-1/+1
| | | | | | | | | | | | | When flushing the TLB at PL2 in response to remapping at stage-2 or VMID rollover, we have a dsb instruction to ensure completion of the command before continuing. Since we only care about other processors for TLB invalidation, use the inner-shareable variant of the dsb instruction instead. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
* ARM: KVM: switch to a dual-step HYP init codeMarc Zyngier2013-04-281-19/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* KVM: ARM: Hypervisor initializationChristoffer Dall2013-01-231-0/+95
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Sets up KVM code to handle all exceptions taken to Hyp mode. When the kernel is booted in Hyp mode, calling an hvc instruction with r0 pointing to the new vectors, the HVBAR is changed to the the vector pointers. This allows subsystems (like KVM here) to execute code in Hyp-mode with the MMU disabled. We initialize other Hyp-mode registers and enables the MMU for Hyp-mode from the id-mapped hyp initialization code. Afterwards, the HVBAR is changed to point to KVM Hyp vectors used to catch guest faults and to switch to Hyp mode to perform a world-switch into a KVM guest. Also provides memory mapping code to map required code pages, data structures, and I/O regions accessed in Hyp mode at the same virtual address as the host kernel virtual addresses, but which conforms to the architectural requirements for translations in Hyp mode. This interface is added in arch/arm/kvm/arm_mmu.c and comprises: - create_hyp_mappings(from, to); - create_hyp_io_mappings(from, to, phys_addr); - free_hyp_pmds(); Reviewed-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
* KVM: ARM: Initial skeleton to compile KVM supportChristoffer Dall2013-01-231-0/+19
Targets KVM support for Cortex A-15 processors. Contains all the framework components, make files, header files, some tracing functionality, and basic user space API. Only supported core is Cortex-A15 for now. Most functionality is in arch/arm/kvm/* or arch/arm/include/asm/kvm_*.h. Reviewed-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
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