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Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing
From: |
Christian Borntraeger |
Subject: |
Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing |
Date: |
Wed, 21 Oct 2020 16:18:19 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 |
On 21.10.20 16:14, David Hildenbrand wrote:
> On 21.10.20 15:43, Janosch Frank wrote:
>> Diag318 fencing needs to be determined on the current VM PV state and
>> not on the state that the VM has when we create the CPU model.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> Fixes: fabdada935 ("s390: guest support for diagnose 0x318")
>> Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>> ---
>> hw/s390x/sclp.c | 10 ++++++++++
>> target/s390x/kvm.c | 3 +--
>> 2 files changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index 0cf2290826..69aba402d3 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -22,6 +22,7 @@
>> #include "hw/s390x/event-facility.h"
>> #include "hw/s390x/s390-pci-bus.h"
>> #include "hw/s390x/ipl.h"
>> +#include "hw/s390x/pv.h"
>>
>> static inline SCLPDevice *get_sclp_device(void)
>> {
>> @@ -142,6 +143,15 @@ static void read_SCP_info(SCLPDevice *sclp, SCCB *sccb)
>> if (s390_has_feat(S390_FEAT_EXTENDED_LENGTH_SCCB)) {
>> s390_get_feat_block(S390_FEAT_TYPE_SCLP_FAC134,
>> &read_info->fac134);
>> + /*
>> + * Diag318 is not available in protected mode and will result
>> + * in an operation exception. As we can dynamically move in
>> + * and out of protected mode, we need to fence the feature
>> + * here rather than when creating the CPU model.
>> + */
>> + if (s390_is_pv()) {
>> + read_info->fac134 &= ~0x80;
>> + }
>
> Hmm, I thought firmware would handle exposing cpu features and similar,
> so we can't temper with it ....
Only the stfle bits.
>
> Can we move that into s390_get_feat_block instead and check against the
> feature bit instead?
No because we want to have this active for !pv and disabled for pv but we switch
this multiple times when doing boot/reboot.
- [PATCH 0/2] s390x: pv: Diag318 fixes, Janosch Frank, 2020/10/21
- [PATCH 1/2] s390x: pv: Remove sclp boundary checks, Janosch Frank, 2020/10/21
- [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/21
- Re: [PATCH 2/2] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/21
- [PATCH] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, Janosch Frank, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, Halil Pasic, 2020/10/22
- Re: [PATCH] s390x: pv: Fix diag318 PV fencing, David Hildenbrand, 2020/10/22