Re: [PATCH v4 5/7] KVM: PPC: clean up redundant kvm_run parameters in assembly
From: Paul Mackerras <hidden>
Date: 2020-05-26 05:59:34
Also in:
kvm, kvmarm, linux-arm-kernel, linux-mips, linux-s390, lkml
On Mon, Apr 27, 2020 at 12:35:12PM +0800, Tianjia Zhang wrote:
In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu' structure. For historical reasons, many kvm-related function parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time. This patch does a unified cleanup of these remaining redundant parameters.
Some of these changes don't look completely correct to me, see below. If you're expecting these patches to go through my tree, I can fix up the patch and commit it (with you as author), noting the changes I made in the commit message. Do you want me to do that?
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/kvm/book3s_interrupts.S b/arch/powerpc/kvm/book3s_interrupts.S index f7ad99d972ce..0eff749d8027 100644 --- a/arch/powerpc/kvm/book3s_interrupts.S +++ b/arch/powerpc/kvm/book3s_interrupts.S@@ -55,8 +55,7 @@ ****************************************************************************/ /* Registers: - * r3: kvm_run pointer - * r4: vcpu pointer + * r3: vcpu pointer */ _GLOBAL(__kvmppc_vcpu_run)@@ -68,8 +67,8 @@ kvm_start_entry: /* Save host state to the stack */ PPC_STLU r1, -SWITCH_FRAME_SIZE(r1) - /* Save r3 (kvm_run) and r4 (vcpu) */ - SAVE_2GPRS(3, r1) + /* Save r3 (vcpu) */ + SAVE_GPR(3, r1) /* Save non-volatile registers (r14 - r31) */ SAVE_NVGPRS(r1)@@ -82,11 +81,11 @@ kvm_start_entry: PPC_STL r0, _LINK(r1) /* Load non-volatile guest state from the vcpu */ - VCPU_LOAD_NVGPRS(r4) + VCPU_LOAD_NVGPRS(r3) kvm_start_lightweight: /* Copy registers into shadow vcpu so we can access them in real mode */ - mr r3, r4 + mr r4, r3
This mr doesn't seem necessary.
bl FUNC(kvmppc_copy_to_svcpu) nop REST_GPR(4, r1)
This should be loading r4 from GPR3(r1), not GPR4(r1) - which is what REST_GPR(4, r1) will do. Then, in the file but not in the patch context, there is this line: PPC_LL r3, GPR4(r1) /* vcpu pointer */ where once again GPR4 needs to be GPR3.
quoted hunk ↗ jump to hunk
@@ -191,10 +190,10 @@ after_sprg3_load: PPC_STL r31, VCPU_GPR(R31)(r7) /* Pass the exit number as 3rd argument to kvmppc_handle_exit */
The comment should be modified to say "2nd" instead of "3rd", otherwise it is confusing. The rest of the patch looks OK. Paul.