Re: [RFC PATCH 12/45] KVM: arm64: pkvm: Unify pkvm_pkvm_teardown_donated_memory() - Jean-Philippe Brucker

From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Sebastian Ene <sebastianene@google.com>
Cc: maz@kernel.org, catalin.marinas@arm.com, will@kernel.org,
	joro@8bytes.org, robin.murphy@arm.com, james.morse@arm.com,
	suzuki.poulose@arm.com, oliver.upton@linux.dev,
	yuzenghui@huawei.com, smostafa@google.com, dbrazdil@google.com,
	ryan.roberts@arm.com, linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.linux.dev, iommu@lists.linux.dev
Subject: Re: [RFC PATCH 12/45] KVM: arm64: pkvm: Unify pkvm_pkvm_teardown_donated_memory()
Date: Tue, 23 Jan 2024 19:49:31 +0000	[thread overview]
Message-ID: <20240123194931.GB40099@myrica> (raw)
In-Reply-To: <ZaVCTuM7KDSWqqaE@google.com>

Hi Seb,

On Mon, Jan 15, 2024 at 02:33:50PM +0000, Sebastian Ene wrote:
> >  int __pkvm_teardown_vm(pkvm_handle_t handle)
> >  {
> >  	size_t vm_size, last_ran_size;
> > @@ -813,19 +802,18 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
> >  		vcpu_mc = &hyp_vcpu->vcpu.arch.pkvm_memcache;
> >  		while (vcpu_mc->nr_pages) {
> >  			addr = pop_hyp_memcache(vcpu_mc, hyp_phys_to_virt);
> > -			push_hyp_memcache(mc, addr, hyp_virt_to_phys);
> > -			unmap_donated_memory_noclear(addr, PAGE_SIZE);
> > +			pkvm_teardown_donated_memory(mc, addr, 0);
> 
> Here we probably need to pass PAGE_SIZE as an argument instead of "0"
> to make sure that we clear out the content of the page before tearing it
> down.

But since it's replacing unmap_donated_memory_noclear(), would that be a
change of behavior?  That would be a separate patch because this one is
just trying to refactor things.

Thanks,
Jean

> 
> >  		}
> >  
> > -		teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
> > +		pkvm_teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
> >  	}
> >  
> >  	last_ran_size = pkvm_get_last_ran_size();
> > -	teardown_donated_memory(mc, hyp_vm->kvm.arch.mmu.last_vcpu_ran,
> > -				last_ran_size);
> > +	pkvm_teardown_donated_memory(mc, hyp_vm->kvm.arch.mmu.last_vcpu_ran,
> > +				     last_ran_size);
> >  
> >  	vm_size = pkvm_get_hyp_vm_size(hyp_vm->kvm.created_vcpus);
> > -	teardown_donated_memory(mc, hyp_vm, vm_size);
> > +	pkvm_teardown_donated_memory(mc, hyp_vm, vm_size);
> >  	hyp_unpin_shared_mem(host_kvm, host_kvm + 1);
> >  	return 0;
> >  
> > -- 
> > 2.39.0
> >
> 
> Thanks,
> Seb

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