* [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm
@ 2019-11-26 22:36 Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm Leonardo Bras
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Leonardo Bras @ 2019-11-26 22:36 UTC (permalink / raw)
To: Paul Mackerras, Benjamin Herrenschmidt, Michael Ellerman
Cc: Leonardo Bras, kvm-ppc, linuxppc-dev, linux-kernel
Replace current->mm by kvm->mm on powerpc/kvm
By replacing, we would reduce the use of 'global' current on code,
relying more in the contents of kvm struct.
On code, I found that in kvm_create_vm() there is:
kvm->mm = current->mm;
And that on every kvm_*_ioctl we have tests like that:
if (kvm->mm != current->mm)
return -EIO;
So this change would be safe.
---
Changes since v2:
- Rebased on torvalds/master and updated the remaining patches.
Changes since v1:
- Fixes possible 'use after free' on kvm_spapr_tce_release (from v1)
- Fixes possible 'use after free' on kvm_vm_ioctl_create_spapr_tce
- Fixes undeclared variable error
Leonardo Bras (2):
powerpc/kvm/book3s: Replace current->mm by kvm->mm
powerpc/kvm/book3e: Replace current->mm by kvm->mm
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
arch/powerpc/kvm/book3s_64_vio.c | 10 ++++++----
arch/powerpc/kvm/book3s_hv.c | 10 +++++-----
arch/powerpc/kvm/booke.c | 2 +-
4 files changed, 14 insertions(+), 12 deletions(-)
--
2.23.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm
2019-11-26 22:36 [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
@ 2019-11-26 22:36 ` Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 2/2] powerpc/kvm/book3e: " Leonardo Bras
2019-11-27 16:20 ` [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2 siblings, 0 replies; 4+ messages in thread
From: Leonardo Bras @ 2019-11-26 22:36 UTC (permalink / raw)
To: Paul Mackerras, Benjamin Herrenschmidt, Michael Ellerman
Cc: Leonardo Bras, kvm-ppc, linuxppc-dev, linux-kernel
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(¤t->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(¤t->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(¤t->mm->mmap_sem);
+ up_read(&kvm->mm->mmap_sem);
goto out_srcu;
}
--
2.23.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3 2/2] powerpc/kvm/book3e: Replace current->mm by kvm->mm
2019-11-26 22:36 [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm Leonardo Bras
@ 2019-11-26 22:36 ` Leonardo Bras
2019-11-27 16:20 ` [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2 siblings, 0 replies; 4+ messages in thread
From: Leonardo Bras @ 2019-11-26 22:36 UTC (permalink / raw)
To: Paul Mackerras, Benjamin Herrenschmidt, Michael Ellerman
Cc: Leonardo Bras, kvm-ppc, linuxppc-dev, linux-kernel
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/booke.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index be9a45874194..fd7bdb4f8f87 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -775,7 +775,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
debug = current->thread.debug;
current->thread.debug = vcpu->arch.dbg_reg;
- vcpu->arch.pgdir = current->mm->pgd;
+ vcpu->arch.pgdir = vcpu->kvm->mm->pgd;
kvmppc_fix_ee_before_entry();
ret = __kvmppc_vcpu_run(kvm_run, vcpu);
--
2.23.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm
2019-11-26 22:36 [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 2/2] powerpc/kvm/book3e: " Leonardo Bras
@ 2019-11-27 16:20 ` Leonardo Bras
2 siblings, 0 replies; 4+ messages in thread
From: Leonardo Bras @ 2019-11-27 16:20 UTC (permalink / raw)
To: Paul Mackerras, Benjamin Herrenschmidt, Michael Ellerman
Cc: kvm-ppc, linuxppc-dev, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 99 bytes --]
Result of Travis-CI testing the change:
https://travis-ci.org/LeoBras/linux-ppc/builds/617712012
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-11-27 16:20 UTC | newest]
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2019-11-26 22:36 [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 1/2] powerpc/kvm/book3s: Replace current->mm by kvm->mm Leonardo Bras
2019-11-26 22:36 ` [PATCH v3 2/2] powerpc/kvm/book3e: " Leonardo Bras
2019-11-27 16:20 ` [PATCH v3 0/2] Replace current->mm by kvm->mm on powerpc/kvm Leonardo Bras
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