diff mbox series

[v2,23/42] KVM: s390: protvirt: Write sthyi data to instruction data area

Message ID 20200214222658.12946-24-borntraeger@de.ibm.com (mailing list archive)
State New, archived
Headers show
Series KVM: s390: Add support for protected VMs | expand

Commit Message

Christian Borntraeger Feb. 14, 2020, 10:26 p.m. UTC 
From: Janosch Frank <frankja@linux.ibm.com>

STHYI data has to go through the bounce buffer.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/kvm/intercept.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Comments

David Hildenbrand Feb. 17, 2020, 2:24 p.m. UTC | #1 
On 14.02.20 23:26, Christian Borntraeger wrote:
> From: Janosch Frank <frankja@linux.ibm.com>
> 
> STHYI data has to go through the bounce buffer.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> [borntraeger@de.ibm.com: patch merging, splitting, fixing]
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/kvm/intercept.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
> index 1e231058e4b3..cfabeecbb777 100644
> --- a/arch/s390/kvm/intercept.c
> +++ b/arch/s390/kvm/intercept.c
> @@ -392,7 +392,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>  		goto out;
>  	}
>  
> -	if (addr & ~PAGE_MASK)
> +	if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK))
>  		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>  
>  	sctns = (void *)get_zeroed_page(GFP_KERNEL);
> @@ -403,10 +403,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>  
>  out:
>  	if (!cc) {
> -		r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
> -		if (r) {
> -			free_page((unsigned long)sctns);
> -			return kvm_s390_inject_prog_cond(vcpu, r);
> +		if (kvm_s390_pv_is_protected(vcpu->kvm)) {

I have the feeling that we might have to think about proper locking for
kvm_s390_pv_is_protected(). We have to make sure there cannot be any
races with user space. Smells like a new r/w lock maybe.
Christian Borntraeger Feb. 17, 2020, 6:40 p.m. UTC | #2 
On 17.02.20 15:24, David Hildenbrand wrote:
> On 14.02.20 23:26, Christian Borntraeger wrote:
>> From: Janosch Frank <frankja@linux.ibm.com>
>>
>> STHYI data has to go through the bounce buffer.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>> [borntraeger@de.ibm.com: patch merging, splitting, fixing]
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  arch/s390/kvm/intercept.c | 15 ++++++++++-----
>>  1 file changed, 10 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
>> index 1e231058e4b3..cfabeecbb777 100644
>> --- a/arch/s390/kvm/intercept.c
>> +++ b/arch/s390/kvm/intercept.c
>> @@ -392,7 +392,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>  		goto out;
>>  	}
>>  
>> -	if (addr & ~PAGE_MASK)
>> +	if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK))
>>  		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>  
>>  	sctns = (void *)get_zeroed_page(GFP_KERNEL);
>> @@ -403,10 +403,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>  
>>  out:
>>  	if (!cc) {
>> -		r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
>> -		if (r) {
>> -			free_page((unsigned long)sctns);
>> -			return kvm_s390_inject_prog_cond(vcpu, r);
>> +		if (kvm_s390_pv_is_protected(vcpu->kvm)) {
> 
> I have the feeling that we might have to think about proper locking for
> kvm_s390_pv_is_protected(). We have to make sure there cannot be any
> races with user space. Smells like a new r/w lock maybe.

I think we can keep that within kvm->lock (for the global changes) and vcpu->mutex. 
All the intercepts only happen within the vcpu run ioctl and that takes the
vcpu->mutex. See my other patch (with  mutex_lock(&vcpu->mutex) and mutex_unlock(&vcpu->mutex)
around the create/destroy functions). lockdep_assert_help is happy and as long as the
pv_handle reflects the state of the control block of that CPU we are good.

I pushed out the patch/rfcs to pv_worktree on kvms390.git.
David Hildenbrand Feb. 17, 2020, 7:16 p.m. UTC | #3 
On 17.02.20 19:40, Christian Borntraeger wrote:
> 
> 
> On 17.02.20 15:24, David Hildenbrand wrote:
>> On 14.02.20 23:26, Christian Borntraeger wrote:
>>> From: Janosch Frank <frankja@linux.ibm.com>
>>>
>>> STHYI data has to go through the bounce buffer.
>>>
>>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>>> [borntraeger@de.ibm.com: patch merging, splitting, fixing]
>>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>>> ---
>>>  arch/s390/kvm/intercept.c | 15 ++++++++++-----
>>>  1 file changed, 10 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
>>> index 1e231058e4b3..cfabeecbb777 100644
>>> --- a/arch/s390/kvm/intercept.c
>>> +++ b/arch/s390/kvm/intercept.c
>>> @@ -392,7 +392,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>>  		goto out;
>>>  	}
>>>  
>>> -	if (addr & ~PAGE_MASK)
>>> +	if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK))
>>>  		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>>  
>>>  	sctns = (void *)get_zeroed_page(GFP_KERNEL);
>>> @@ -403,10 +403,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
>>>  
>>>  out:
>>>  	if (!cc) {
>>> -		r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
>>> -		if (r) {
>>> -			free_page((unsigned long)sctns);
>>> -			return kvm_s390_inject_prog_cond(vcpu, r);
>>> +		if (kvm_s390_pv_is_protected(vcpu->kvm)) {
>>
>> I have the feeling that we might have to think about proper locking for
>> kvm_s390_pv_is_protected(). We have to make sure there cannot be any
>> races with user space. Smells like a new r/w lock maybe.
> 
> I think we can keep that within kvm->lock (for the global changes) and vcpu->mutex. 
> All the intercepts only happen within the vcpu run ioctl and that takes the
> vcpu->mutex. See my other patch (with  mutex_lock(&vcpu->mutex) and mutex_unlock(&vcpu->mutex)
> around the create/destroy functions). lockdep_assert_help is happy and as long as the
> pv_handle reflects the state of the control block of that CPU we are good.
> 
> I pushed out the patch/rfcs to pv_worktree on kvms390.git.

Fine with me!
diff mbox series

Patch

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 1e231058e4b3..cfabeecbb777 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -392,7 +392,7 @@  int handle_sthyi(struct kvm_vcpu *vcpu)
 		goto out;
 	}
 
-	if (addr & ~PAGE_MASK)
+	if (!kvm_s390_pv_is_protected(vcpu->kvm) && (addr & ~PAGE_MASK))
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
 	sctns = (void *)get_zeroed_page(GFP_KERNEL);
@@ -403,10 +403,15 @@  int handle_sthyi(struct kvm_vcpu *vcpu)
 
 out:
 	if (!cc) {
-		r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
-		if (r) {
-			free_page((unsigned long)sctns);
-			return kvm_s390_inject_prog_cond(vcpu, r);
+		if (kvm_s390_pv_is_protected(vcpu->kvm)) {
+			memcpy((void *)(sida_origin(vcpu->arch.sie_block)),
+			       sctns, PAGE_SIZE);
+		} else {
+			r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
+			if (r) {
+				free_page((unsigned long)sctns);
+				return kvm_s390_inject_prog_cond(vcpu, r);
+			}
 		}
 	}