On 27.06.22 13:02, Roger Pau Monné wrote:
On Mon, Jun 27, 2022 at 12:40:41PM +0200, Juergen Gross wrote:On 27.06.22 12:28, Roger Pau Monné wrote:On Thu, Mar 24, 2022 at 03:01:31PM +0100, Juergen Gross wrote:The entry point used for the vcpu_op hypercall on Arm is different from the one on x86 today, as some of the common sub-ops are not supported on Arm. The Arm specific handler filters out the not supported sub-ops and then calls the common handler. This leads to the weird call hierarchy:do_arm_vcpu_op() do_vcpu_op() arch_do_vcpu_op() Clean this up by renaming do_vcpu_op() to common_vcpu_op() and arch_do_vcpu_op() in each architecture to do_vcpu_op(). This way one of above calls can be avoided without restricting any potential future use of common sub-ops for Arm.Wouldn't it be more natural to have do_vcpu_op() contain the common code (AFAICT handlers for VCPUOP_register_{vcpu_info,runstate_memory_area}) and then everything else handled by the x86 arch_do_vcpu_op() handler? I find the common prefix misleading, as not all the VCPUOP hypercalls are available to all the architectures.This would end up in Arm suddenly supporting the sub-ops it doesn't (want to) support today. Otherwise it would make no sense that Arm has a dedicated entry for this hypercall.My preference would be for a common do_vcpu_op() that just contains handlers for VCPUOP_register_{vcpu_info,runstate_memory_area} and then an empty arch_ handler for Arm, and everything else moved to the x86 arch_ handler. That obviously implies some code churn, but results in a cleaner implementation IMO.
I'd be fine with that. I did it in V2 of the (then secret) series, and Jan replied: I'm afraid I don't agree with this movement. I could see things getting moved that are purely PV (on the assumption that no new PV ports will appear), but anything that's also usable by PVH / HVM ought to be usable in principle also by Arm or other PV-free ports. Juergen
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