[PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm

Leonardo Bras
2019-11-26T22:36:30Z

Given that in kvm_create_vm() there is:
kvm->mm = current->mm;

And that on every kvm_*_ioctl we have:
if (kvm->mm != current->mm)
return -EIO;

I see no reason to keep using current->mm instead of kvm->mm.

By doing so, we would reduce the use of 'global' variables on code, relying
more in the contents of kvm struct.

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
arch/powerpc/kvm/book3s_64_vio.c | 10 ++++++----
arch/powerpc/kvm/book3s_hv.c | 10 +++++-----
3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index d381526c5c9b..6c372f5c61b6 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -284,7 +284,7 @@ static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
/* Protect linux PTE lookup from page table destruction */
rcu_read_lock_sched(); /* this disables preemption too */
ret = kvmppc_do_h_enter(kvm, flags, pte_index, pteh, ptel,
- current->mm->pgd, false, pte_idx_ret);
+ kvm->mm->pgd, false, pte_idx_ret);
rcu_read_unlock_sched();
if (ret = H_TOO_HARD) {
/* this can't happen */
@@ -573,7 +573,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
is_ci = false;
pfn = 0;
page = NULL;
- mm = current->mm;
+ mm = kvm->mm;
pte_size = PAGE_SIZE;
writing = (dsisr & DSISR_ISSTORE) != 0;
/* If writing != 0, then the HPTE must allow writing, if we get here */
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 883a66e76638..ee6c103bb7d5 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -253,10 +253,11 @@ static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
}
}

+ account_locked_vm(kvm->mm,
+ kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
+
kvm_put_kvm(stt->kvm);

- account_locked_vm(current->mm,
- kvmppc_stt_pages(kvmppc_tce_pages(stt->size)), false);
call_rcu(&stt->rcu, release_spapr_tce_table);

return 0;
@@ -272,6 +273,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
{
struct kvmppc_spapr_tce_table *stt = NULL;
struct kvmppc_spapr_tce_table *siter;
+ struct mm_struct *mm = kvm->mm;
unsigned long npages, size = args->size;
int ret = -ENOMEM;

@@ -280,7 +282,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
return -EINVAL;

npages = kvmppc_tce_pages(size);
- ret = account_locked_vm(current->mm, kvmppc_stt_pages(npages), true);
+ ret = account_locked_vm(mm, kvmppc_stt_pages(npages), true);
if (ret)
return ret;

@@ -326,7 +328,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,

kfree(stt);
fail_acct:
- account_locked_vm(current->mm, kvmppc_stt_pages(npages), false);
+ account_locked_vm(mm, kvmppc_stt_pages(npages), false);
return ret;
}

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index ec5c0379296a..d3baa23396e6 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -4263,7 +4263,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
user_vrsave = mfspr(SPRN_VRSAVE);

vcpu->arch.wqp = &vcpu->arch.vcore->wq;
- vcpu->arch.pgdir = current->mm->pgd;
+ vcpu->arch.pgdir = kvm->mm->pgd;
vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST;

do {
@@ -4595,14 +4595,14 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)

/* Look up the VMA for the start of this memory slot */
hva = memslot->userspace_addr;
- down_read(&current->mm->mmap_sem);
- vma = find_vma(current->mm, hva);
+ down_read(&kvm->mm->mmap_sem);
+ vma = find_vma(kvm->mm, hva);
if (!vma || vma->vm_start > hva || (vma->vm_flags & VM_IO))
goto up_out;

psize = vma_kernel_pagesize(vma);

- up_read(&current->mm->mmap_sem);
+ up_read(&kvm->mm->mmap_sem);

/* We can handle 4k, 64k or 16M pages in the VRMA */
if (psize >= 0x1000000)
@@ -4635,7 +4635,7 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
return err;

up_out:
- up_read(&current->mm->mmap_sem);
+ up_read(&kvm->mm->mmap_sem);
goto out_srcu;
}

--
2.23.0