linux-kernel - [PATCH v3 0/4] KVM: s390: Fix minor bugs in STFLE shadowing

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Message-Id: <20231108171229.3404476-1-nsg@linux.ibm.com>
Date:   Wed,  8 Nov 2023 18:12:25 +0100
From:   Nina Schoetterl-Glausch <nsg@...ux.ibm.com>
To:     Heiko Carstens <hca@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Nina Schoetterl-Glausch <nsg@...ux.ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Vasily Gorbik <gor@...ux.ibm.com>
Cc:     Sven Schnelle <svens@...ux.ibm.com>, linux-s390@...r.kernel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 0/4] KVM: s390: Fix minor bugs in STFLE shadowing

v2 -> v3 (range-diff below):
 * pick up tags (thanks Claudio)
 * reverse Christmas tree

v1 -> v2:
 * pick up tags (thanks {Claudio, David})
 * drop Fixes tag on cleanup patch, change message (thanks David)
 * drop Fixes tag on second patch since the length of the facility list
   copied wasn't initially specified and only clarified in later
   revisions
 * use READ/WRITE_ONCE (thanks {David, Heiko})

Improve the STFLE vsie implementation.
Firstly, fix a bug concerning the identification if the guest is
intending to use interpretive execution for STFLE for its guest.
Secondly, decrease the amount of guest memory accessed to the
minimum.
Also do some (optional) cleanups.

Nina Schoetterl-Glausch (4):
  KVM: s390: vsie: Fix STFLE interpretive execution identification
  KVM: s390: vsie: Fix length of facility list shadowed
  KVM: s390: cpu model: Use proper define for facility mask size
  KVM: s390: Minor refactor of base/ext facility lists

 arch/s390/include/asm/facility.h |  6 +++++
 arch/s390/include/asm/kvm_host.h |  2 +-
 arch/s390/kernel/Makefile        |  2 +-
 arch/s390/kernel/facility.c      | 21 +++++++++++++++
 arch/s390/kvm/kvm-s390.c         | 44 ++++++++++++++------------------
 arch/s390/kvm/vsie.c             | 15 +++++++++--
 6 files changed, 61 insertions(+), 29 deletions(-)
 create mode 100644 arch/s390/kernel/facility.c

Range-diff against v2:
1:  de77a2c36786 = 1:  de77a2c36786 KVM: s390: vsie: Fix STFLE interpretive execution identification
2:  f3b189627e96 ! 2:  e4b44c4d2400 KVM: s390: vsie: Fix length of facility list shadowed
    @@ Commit message
         case we'd wrongly inject a validity intercept.
     
         Acked-by: David Hildenbrand <david@...hat.com>
    +    Reviewed-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
         Signed-off-by: Nina Schoetterl-Glausch <nsg@...ux.ibm.com>
     
      ## arch/s390/include/asm/facility.h ##
    @@ arch/s390/kernel/facility.c (new)
     +unsigned int stfle_size(void)
     +{
     +	static unsigned int size;
    -+	u64 dummy;
     +	unsigned int r;
    ++	u64 dummy;
     +
     +	r = READ_ONCE(size);
     +	if (!r) {
3:  4907bb8fb2bc ! 3:  8b02ac33defb KVM: s390: cpu model: Use proper define for facility mask size
    @@ Commit message
         S390_ARCH_FAC_LIST_SIZE_U64 for defining the fac_mask array.
         Note that both values are the same, there is no functional change.
     
    +    Reviewed-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
         Signed-off-by: Nina Schoetterl-Glausch <nsg@...ux.ibm.com>
     
      ## arch/s390/include/asm/kvm_host.h ##
4:  2745898a22c3 ! 4:  a592be823576 KVM: s390: Minor refactor of base/ext facility lists
    @@ Commit message
         Make the constraint of that number on kvm_s390_fac_base obvious.
         Get rid of implicit double anding of stfle_fac_list.
     
    +    Reviewed-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
         Signed-off-by: Nina Schoetterl-Glausch <nsg@...ux.ibm.com>
     
     

base-commit: 05d3ef8bba77c1b5f98d941d8b2d4aeab8118ef1
-- 
2.39.2