On Wed, Mar 05, 2025, Greg KH wrote:

On Wed, Mar 05, 2025 at 03:14:13PM +0100, Christian Zigotzky wrote:

quoted

Hi All,

The stable long-term kernel 6.12.17 cannot compile with KVM HV support for e5500 PowerPC machines anymore.

Bug report: https://github.com/chzigotzky/kernels/issues/6

Kernel config: https://github.com/chzigotzky/kernels/blob/6_12/configs/x5000_defconfig

Error messages:

arch/powerpc/kvm/e500_mmu_host.c: In function 'kvmppc_e500_shadow_map':
arch/powerpc/kvm/e500_mmu_host.c:447:9: error: implicit declaration of function '__kvm_faultin_pfn' [-Werror=implicit-function-declaration]
   pfn = __kvm_faultin_pfn(slot, gfn, FOLL_WRITE, NULL, &page);
         ^~~~~~~~~~~~~~~~~
  CC      kernel/notifier.o
arch/powerpc/kvm/e500_mmu_host.c:500:2: error: implicit declaration of function 'kvm_release_faultin_page'; did you mean 'kvm_read_guest_page'? [-Werror=implicit-function-declaration]
  kvm_release_faultin_page(kvm, page, !!ret, writable);

After that, I compiled it without KVM HV support.

Kernel config: https://github.com/chzigotzky/kernels/blob/6_12/configs/e5500_defconfig

Please check the error messages.

Odd, what commit caused this problem?  Any hint as to what commit is
missing to fix it?

833f69be62ac.  It most definitely should be reverted.  The "dependency" for commit
87ecfdbc699c ("KVM: e500: always restore irqs") is a superficial code conflict.

Oof.  The same buggy patch was queue/proposed for all stable trees from 5.4 onward,
but it look like it only landed in 6.1, 6.6, and 6.12.  I'll send reverts.

commit 833f69be62ac366b5c23b4a6434389e470dd5c7f
Author:     Sean Christopherson [off-list ref]
AuthorDate: Thu Oct 10 11:23:56 2024 -0700
Commit:     Greg Kroah-Hartman [off-list ref]
CommitDate: Mon Feb 17 10:04:56 2025 +0100

    KVM: PPC: e500: Use __kvm_faultin_pfn() to handle page faults
    
    [ Upstream commit 419cfb983ca93e75e905794521afefcfa07988bb ]
    
    Convert PPC e500 to use __kvm_faultin_pfn()+kvm_release_faultin_page(),
    and continue the inexorable march towards the demise of
    kvm_pfn_to_refcounted_page().
    
    Signed-off-by: Sean Christopherson [off-list ref]
    Tested-by: Dmitry Osipenko [off-list ref]
    Signed-off-by: Paolo Bonzini [off-list ref]
    Message-ID: [ref]
    Stable-dep-of: 87ecfdbc699c ("KVM: e500: always restore irqs")
    Signed-off-by: Sasha Levin [off-list ref]