kernel.git/arch/s390/kvm, branch linux-4.14.y

KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field

2022-12-14T10:26:13Z

commit 0dd4cdccdab3d74bd86b868768a7dca216bcce7e upstream. We recently experienced some weird huge time jumps in nested guests when rebooting them in certain cases. After adding some debug code to the epoch handling in vsie.c (thanks to David Hildenbrand for the idea!), it was obvious that the "epdx" field (the multi-epoch extension) did not get set to 0xff in case the "epoch" field was negative. Seems like the code misses to copy the value from the epdx field from the guest to the shadow control block. By doing so, the weird time jumps are gone in our scenarios. Link: https://bugzilla.redhat.com/show_bug.cgi?id=2140899 Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support") Signed-off-by: Thomas Huth Reviewed-by: Christian Borntraeger Acked-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Reviewed-by: Janosch Frank Cc: stable@vger.kernel.org # 4.19+ Link: https://lore.kernel.org/r/20221123090833.292938-1-thuth@redhat.com Message-Id: <20221123090833.292938-1-thuth@redhat.com> Signed-off-by: Janosch Frank Signed-off-by: Greg Kroah-Hartman

KVM: s390: split kvm_s390_real_to_abs

2021-05-22T08:57:26Z

commit c5d1f6b531e68888cbe6718b3f77a60115d58b9c upstream. A new function _kvm_s390_real_to_abs will apply prefixing to a real address with a given prefix value. The old kvm_s390_real_to_abs becomes now a wrapper around the new function. This is needed to avoid code duplication in vSIE. Signed-off-by: Claudio Imbrenda Reviewed-by: David Hildenbrand Reviewed-by: Thomas Huth Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210322140559.500716-2-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: fix guarded storage control register handling

2021-05-22T08:57:26Z

commit 44bada28219031f9e8e86b84460606efa57b871e upstream. store_regs_fmt2() has an ordering problem: first the guarded storage facility is enabled on the local cpu, then preemption disabled, and then the STGSC (store guarded storage controls) instruction is executed. If the process gets scheduled away between enabling the guarded storage facility and before preemption is disabled, this might lead to a special operation exception and therefore kernel crash as soon as the process is scheduled back and the STGSC instruction is executed. Fixes: 4e0b1ab72b8a ("KVM: s390: gs support for kvm guests") Signed-off-by: Heiko Carstens Reviewed-by: Christian Borntraeger Reviewed-by: David Hildenbrand Reviewed-by: Janosch Frank Reviewed-by: Cornelia Huck Cc: # 4.12 Link: https://lore.kernel.org/r/20210415080127.1061275-1-hca@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: split kvm_s390_logical_to_effective

2021-05-22T08:57:26Z

commit f85f1baaa18932a041fd2b1c2ca6cfd9898c7d2b upstream. Split kvm_s390_logical_to_effective to a generic function called _kvm_s390_logical_to_effective. The new function takes a PSW and an address and returns the address with the appropriate bits masked off. The old function now calls the new function with the appropriate PSW from the vCPU. This is needed to avoid code duplication for vSIE. Signed-off-by: Claudio Imbrenda Reviewed-by: Christian Borntraeger Cc: stable@vger.kernel.org # for VSIE: correctly handle MVPG when in VSIE Link: https://lore.kernel.org/r/20210302174443.514363-2-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: vsie: Fix delivery of addressing exceptions

2020-04-24T06:00:39Z

commit 4d4cee96fb7a3cc53702a9be8299bf525be4ee98 upstream. Whenever we get an -EFAULT, we failed to read in guest 2 physical address space. Such addressing exceptions are reported via a program intercept to the nested hypervisor. We faked the intercept, we have to return to guest 2. Instead, right now we would be returning -EFAULT from the intercept handler, eventually crashing the VM. the correct thing to do is to return 1 as rc == 1 is the internal representation of "we have to go back into g2". Addressing exceptions can only happen if the g2->g3 page tables reference invalid g2 addresses (say, either a table or the final page is not accessible - so something that basically never happens in sane environments. Identified by manual code inspection. Fixes: a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization") Cc: # v4.8+ Signed-off-by: David Hildenbrand Link: https://lore.kernel.org/r/20200403153050.20569-3-david@redhat.com Reviewed-by: Claudio Imbrenda Reviewed-by: Christian Borntraeger [borntraeger@de.ibm.com: fix patch description] Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: ENOTSUPP -> EOPNOTSUPP fixups

2020-02-28T15:35:58Z

[ Upstream commit c611990844c28c61ca4b35ff69d3a2ae95ccd486 ] There is no ENOTSUPP for userspace. Reported-by: Julian Wiedmann Fixes: 519783935451 ("KVM: s390: introduce ais mode modify function") Fixes: 2c1a48f2e5ed ("KVM: S390: add new group for flic") Reviewed-by: Cornelia Huck Reviewed-by: Thomas Huth Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin

KVM: s390: do not clobber registers during guest reset/store status

2020-02-14T21:32:20Z

[ Upstream commit 55680890ea78be0df5e1384989f1be835043c084 ] The initial CPU reset clobbers the userspace fpc and the store status ioctl clobbers the guest acrs + fpr. As these calls are only done via ioctl (and not via vcpu_run), no CPU context is loaded, so we can (and must) act directly on the sync regs, not on the thread context. Cc: stable@kernel.org Fixes: e1788bb995be ("KVM: s390: handle floating point registers in the run ioctl not in vcpu_put/load") Fixes: 31d8b8d41a7e ("KVM: s390: handle access registers in the run ioctl not in vcpu_put/load") Signed-off-by: Christian Borntraeger Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Janosch Frank Link: https://lore.kernel.org/r/20200131100205.74720-2-frankja@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin

KVM: s390: unregister debug feature on failing arch init

2019-12-05T14:37:30Z

[ Upstream commit 308c3e6673b012beecb96ef04cc65f4a0e7cdd99 ] Make sure the debug feature and its allocated resources get released upon unsuccessful architecture initialization. A related indication of the issue will be reported as kernel message. Signed-off-by: Michael Mueller Reviewed-by: Cornelia Huck Reviewed-by: Pierre Morel Reviewed-by: David Hildenbrand Message-Id: <20181130143215.69496-2-mimu@linux.ibm.com> Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin

kvm: Convert kvm_lock to a mutex

2019-11-12T18:19:05Z

commit 0d9ce162cf46c99628cc5da9510b959c7976735b upstream. It doesn't seem as if there is any particular need for kvm_lock to be a spinlock, so convert the lock to a mutex so that sleepable functions (in particular cond_resched()) can be called while holding it. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

KVM: s390: Test for bad access register and size at the start of S390_MEM_OP

2019-10-11T16:18:27Z

commit a13b03bbb4575b350b46090af4dfd30e735aaed1 upstream. If the KVM_S390_MEM_OP ioctl is called with an access register >= 16, then there is certainly a bug in the calling userspace application. We check for wrong access registers, but only if the vCPU was already in the access register mode before (i.e. the SIE block has recorded it). The check is also buried somewhere deep in the calling chain (in the function ar_translation()), so this is somewhat hard to find. It's better to always report an error to the userspace in case this field is set wrong, and it's safer in the KVM code if we block wrong values here early instead of relying on a check somewhere deep down the calling chain, so let's add another check to kvm_s390_guest_mem_op() directly. We also should check that the "size" is non-zero here (thanks to Janosch Frank for the hint!). If we do not check the size, we could call vmalloc() with this 0 value, and this will cause a kernel warning. Signed-off-by: Thomas Huth Link: https://lkml.kernel.org/r/20190829122517.31042-1-thuth@redhat.com Reviewed-by: Cornelia Huck Reviewed-by: Janosch Frank Reviewed-by: David Hildenbrand Cc: stable@vger.kernel.org Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman