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    Subject[PATCH 5.4 415/434] KVM: PPC: Book3S HV: Fix regression on big endian hosts
    Date
    From: Marcus Comstedt <marcus@mc.pp.se>

    commit 228b607d8ea1b7d4561945058d5692709099d432 upstream.

    VCPU_CR is the offset of arch.regs.ccr in kvm_vcpu.
    arch/powerpc/include/asm/kvm_host.h defines arch.regs as a struct
    pt_regs, and arch/powerpc/include/asm/ptrace.h defines the ccr field
    of pt_regs as "unsigned long ccr". Since unsigned long is 64 bits, a
    64-bit load needs to be used to load it, unless an endianness specific
    correction offset is added to access the desired subpart. In this
    case there is no reason to _not_ use a 64 bit load though.

    Fixes: 6c85b7bc637b ("powerpc/kvm: Use UV_RETURN ucall to return to ultravisor")
    Cc: stable@vger.kernel.org # v5.4+
    Signed-off-by: Marcus Comstedt <marcus@mc.pp.se>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/20191215094900.46740-1-marcus@mc.pp.se
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/powerpc/kvm/book3s_hv_rmhandlers.S | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
    +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
    @@ -1117,7 +1117,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
    ld r7, VCPU_GPR(R7)(r4)
    bne ret_to_ultra

    - lwz r0, VCPU_CR(r4)
    + ld r0, VCPU_CR(r4)
    mtcr r0

    ld r0, VCPU_GPR(R0)(r4)
    @@ -1137,7 +1137,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
    * R3 = UV_RETURN
    */
    ret_to_ultra:
    - lwz r0, VCPU_CR(r4)
    + ld r0, VCPU_CR(r4)
    mtcr r0

    ld r0, VCPU_GPR(R3)(r4)

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