> On 22-Jul-2020, at 10:07 AM, Michael Ellerman <m...@ellerman.id.au> wrote: > > Athira Rajeev <atraj...@linux.vnet.ibm.com > <mailto:atraj...@linux.vnet.ibm.com>> writes: >>> On 21-Jul-2020, at 9:24 AM, Paul Mackerras <pau...@ozlabs.org> wrote: >>> On Fri, Jul 17, 2020 at 10:38:14AM -0400, Athira Rajeev wrote: >>>> Currently `kvm_vcpu_arch` stores all Monitor Mode Control registers >>>> in a flat array in order: mmcr0, mmcr1, mmcra, mmcr2, mmcrs >>>> Split this to give mmcra and mmcrs its own entries in vcpu and >>>> use a flat array for mmcr0 to mmcr2. This patch implements this >>>> cleanup to make code easier to read. >>> >>> Changing the way KVM stores these values internally is fine, but >>> changing the user ABI is not. This part: >>> >>>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h >>>> b/arch/powerpc/include/uapi/asm/kvm.h >>>> index 264e266..e55d847 100644 >>>> --- a/arch/powerpc/include/uapi/asm/kvm.h >>>> +++ b/arch/powerpc/include/uapi/asm/kvm.h >>>> @@ -510,8 +510,8 @@ struct kvm_ppc_cpu_char { >>>> >>>> #define KVM_REG_PPC_MMCR0 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x10) >>>> #define KVM_REG_PPC_MMCR1 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x11) >>>> -#define KVM_REG_PPC_MMCRA (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x12) >>>> -#define KVM_REG_PPC_MMCR2 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x13) >>>> +#define KVM_REG_PPC_MMCR2 (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x12) >>>> +#define KVM_REG_PPC_MMCRA (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x13) >>> >>> means that existing userspace programs that used to work would now be >>> broken. That is not acceptable (breaking the user ABI is only ever >>> acceptable with a very compelling reason). So NAK to this part of the >>> patch. >> >> Hi Paul >> >> Thanks for checking the patch. I understood your point on user ABI breakage >> that this particular change can cause. >> I will retain original KVM_REG_PPC_MMCRA and KVM_REG_PPC_MMCR2 order in >> `kvm.h` >> And with that, additionally I will need below change ( on top of current >> patch ) for my clean up updates for kvm cpu MMCR to work, >> Because now mmcra and mmcrs will have its own entries in vcpu and is not >> part of the mmcr[] array >> Please suggest if this looks good > > I did the same patch I think in my testing branch, it's here: > > https://github.com/linuxppc/linux/commit/daea78154eff1b7e2f36be05a8f95feb5a588912 > > <https://github.com/linuxppc/linux/commit/daea78154eff1b7e2f36be05a8f95feb5a588912> > > > Can you please check that matches what you sent.
Hi Michael, Yes, it matches. Thanks for making this change. > > cheers > >> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c >> index 3f90eee261fc..b10bb404f0d5 100644 >> --- a/arch/powerpc/kvm/book3s_hv.c >> +++ b/arch/powerpc/kvm/book3s_hv.c >> @@ -1679,10 +1679,13 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu >> *vcpu, u64 id, >> case KVM_REG_PPC_UAMOR: >> *val = get_reg_val(id, vcpu->arch.uamor); >> break; >> - case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR2: >> + case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR1: >> i = id - KVM_REG_PPC_MMCR0; >> *val = get_reg_val(id, vcpu->arch.mmcr[i]); >> break; >> + case KVM_REG_PPC_MMCR2: >> + *val = get_reg_val(id, vcpu->arch.mmcr[2]); >> + break; >> case KVM_REG_PPC_MMCRA: >> *val = get_reg_val(id, vcpu->arch.mmcra); >> break; >> @@ -1906,10 +1909,13 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu >> *vcpu, u64 id, >> case KVM_REG_PPC_UAMOR: >> vcpu->arch.uamor = set_reg_val(id, *val); >> break; >> - case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR2: >> + case KVM_REG_PPC_MMCR0 ... KVM_REG_PPC_MMCR1: >> i = id - KVM_REG_PPC_MMCR0; >> vcpu->arch.mmcr[i] = set_reg_val(id, *val); >> break; >> + case KVM_REG_PPC_MMCR2: >> + vcpu->arch.mmcr[2] = set_reg_val(id, *val); >> + break; >> case KVM_REG_PPC_MMCRA: >> vcpu->arch.mmcra = set_reg_val(id, *val); >> break; >> — >> >> >>> >>> Regards, >>> Paul.
