kernel/linux.git/arch/powerpc/kvm/emulate.c, branch linux-4.4.y

KVM: PPC: Book3S PR: Fix illegal opcode emulation

2017-03-26T10:13:18+00:00

commit 708e75a3ee750dce1072134e630d66c4e6eaf63c upstream. If kvmppc_handle_exit_pr() calls kvmppc_emulate_instruction() to emulate one instruction (in the BOOK3S_INTERRUPT_H_EMUL_ASSIST case), it calls kvmppc_core_queue_program() afterwards if kvmppc_emulate_instruction() returned EMULATE_FAIL, so the guest gets an program interrupt for the illegal opcode. However, the kvmppc_emulate_instruction() also tried to inject a program exception for this already, so the program interrupt gets injected twice and the return address in srr0 gets destroyed. All other callers of kvmppc_emulate_instruction() are also injecting a program interrupt, and since the callers have the right knowledge about the srr1 flags that should be used, it is the function kvmppc_emulate_instruction() that should _not_ inject program interrupts, so remove the kvmppc_core_queue_program() here. This fixes the issue discovered by Laurent Vivier with kvm-unit-tests where the logs are filled with these messages when the test tries to execute an illegal instruction: Couldn't emulate instruction 0x00000000 (op 0 xop 0) kvmppc_handle_exit_pr: emulation at 700 failed (00000000) Signed-off-by: Thomas Huth Reviewed-by: Alexander Graf Tested-by: Laurent Vivier Signed-off-by: Paul Mackerras Cc: Sumit Semwal Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Pass enum to kvmppc_get_last_inst

2014-09-22T08:11:36+00:00

The kvmppc_get_last_inst function recently received a facelift that allowed us to pass an enum of the type of instruction we want to read into it rather than an unreadable boolean. Unfortunately, not all callers ended up passing the enum. This wasn't really an issue as "true" and "false" happen to match the two enum values we have, but it's still hard to read. Update all callers of kvmppc_get_last_inst() to follow the new calling convention. Signed-off-by: Alexander Graf

powerpc/kvm: support to handle sw breakpoint

2014-09-22T08:11:35+00:00

This patch adds kernel side support for software breakpoint. Design is that, by using an illegal instruction, we trap to hypervisor via Emulation Assistance interrupt, where we check for the illegal instruction and accordingly we return to Host or Guest. Patch also adds support for software breakpoint in PR KVM. Signed-off-by: Madhavan Srinivasan Signed-off-by: Alexander Graf

KVM: PPC: Separate loadstore emulation from priv emulation

2014-07-28T16:30:10+00:00

Today the instruction emulator can get called via 2 separate code paths. It can either be called by MMIO emulation detection code or by privileged instruction traps. This is bad, as both code paths prepare the environment differently. For MMIO emulation we already know the virtual address we faulted on, so instructions there don't have to actually fetch that information. Split out the two separate use cases into separate files. Signed-off-by: Alexander Graf

KVM: PPC: Allow kvmppc_get_last_inst() to fail

2014-07-28T13:23:14+00:00

On book3e, guest last instruction is read on the exit path using load external pid (lwepx) dedicated instruction. This load operation may fail due to TLB eviction and execute-but-not-read entries. This patch lay down the path for an alternative solution to read the guest last instruction, by allowing kvmppc_get_lat_inst() function to fail. Architecture specific implmentations of kvmppc_load_last_inst() may read last guest instruction and instruct the emulation layer to re-execute the guest in case of failure. Make kvmppc_get_last_inst() definition common between architectures. Signed-off-by: Mihai Caraman Signed-off-by: Alexander Graf

KVM: PPC: Make shared struct aka magic page guest endian

2014-05-30T12:26:21+00:00

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

KVM: PPC: Book3S: MMIO emulation support for little endian guests

2014-01-27T15:00:39+00:00

MMIO emulation reads the last instruction executed by the guest and then emulates. If the guest is running in Little Endian order, or more generally in a different endian order of the host, the instruction needs to be byte-swapped before being emulated. This patch adds a helper routine which tests the endian order of the host and the guest in order to decide whether a byteswap is needed or not. It is then used to byteswap the last instruction of the guest in the endian order of the host before MMIO emulation is performed. Finally, kvmppc_handle_load() of kvmppc_handle_store() are modified to reverse the endianness of the MMIO if required. Signed-off-by: Cédric Le Goater [agraf: add booke handling] Signed-off-by: Alexander Graf

kvm: powerpc: book3s: Allow the HV and PR selection per virtual machine

2013-10-17T16:42:36+00:00

This moves the kvmppc_ops callbacks to be a per VM entity. This enables us to select HV and PR mode when creating a VM. We also allow both kvm-hv and kvm-pr kernel module to be loaded. To achieve this we move /dev/kvm ownership to kvm.ko module. Depending on which KVM mode we select during VM creation we take a reference count on respective module Signed-off-by: Aneesh Kumar K.V [agraf: fix coding style] Signed-off-by: Alexander Graf

kvm: powerpc: book3s: Support building HV and PR KVM as module

2013-10-17T13:45:35+00:00

Signed-off-by: Aneesh Kumar K.V [agraf: squash in compile fix] Signed-off-by: Alexander Graf

kvm: powerpc: Add kvmppc_ops callback

2013-10-17T13:24:26+00:00

This patch add a new callback kvmppc_ops. This will help us in enabling both HV and PR KVM together in the same kernel. The actual change to enable them together is done in the later patch in the series. Signed-off-by: Aneesh Kumar K.V [agraf: squash in booke changes] Signed-off-by: Alexander Graf