kernel.git/arch/s390/kvm, branch linux-5.13.y

KVM: s390: index kvm->arch.idle_mask by vcpu_idx

2021-09-15T08:00:57Z

commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream. While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true, it may not always be, and we must not rely on this. Reason is that KVM decides the vcpu_idx, userspace decides the vcpu_id, thus the two might not match. Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies that code like for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { vcpu = kvm_get_vcpu(kvm, vcpu_id); do_stuff(vcpu); } is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an vcpu_id. The trouble is, we do actually use kvm->arch.idle_mask like this. To fix this problem we have two options. Either use kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id, or switch to indexing via vcpu_idx. The latter is preferable for obvious reasons. Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to indexing it by vcpu_idx. To keep gisa_int.kicked_mask indexed by the same index as idle_mask lets make the same change for it as well. Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array") Signed-off-by: Halil Pasic Reviewed-by: Christian Bornträger Reviewed-by: Claudio Imbrenda Cc: # 3.15+ Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: get rid of register asm usage

2021-07-14T15:06:29Z

[ Upstream commit 4fa3b91bdee1b08348c82660668ca0ca34e271ad ] Using register asm statements has been proven to be very error prone, especially when using code instrumentation where gcc may add function calls, which clobbers register contents in an unexpected way. Therefore get rid of register asm statements in kvm code, even though there is currently nothing wrong with them. This way we know for sure that this bug class won't be introduced here. Signed-off-by: Heiko Carstens Reviewed-by: Christian Borntraeger Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Reviewed-by: Claudio Imbrenda Link: https://lore.kernel.org/r/20210621140356.1210771-1-hca@linux.ibm.com [borntraeger@de.ibm.com: checkpatch strict fix] Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin

KVM: s390: prepare for hugepage vmalloc

2021-06-25T02:40:54Z

The Create Secure Configuration Ultravisor Call does not support using large pages for the virtual memory area. This is a hardware limitation. This patch replaces the vzalloc call with an almost equivalent call to the newly introduced vmalloc_no_huge function, which guarantees that only small pages will be used for the backing. The new call will not clear the allocated memory, but that has never been an actual requirement. Link: https://lkml.kernel.org/r/20210614132357.10202-3-imbrenda@linux.ibm.com Fixes: 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Claudio Imbrenda Reviewed-by: Janosch Frank Acked-by: Christian Borntraeger Acked-by: Nicholas Piggin Reviewed-by: David Hildenbrand Cc: Nicholas Piggin Cc: Uladzislau Rezki (Sony) Cc: Catalin Marinas Cc: Thomas Gleixner Cc: Ingo Molnar Cc: David Rientjes Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

KVM: s390x: implement KVM_CAP_SET_GUEST_DEBUG2

2021-04-17T12:31:03Z

Define KVM_GUESTDBG_VALID_MASK and use it to implement this capabiity. Compile tested only. Signed-off-by: Maxim Levitsky Message-Id: <20210401135451.1004564-6-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini

Merge tag 'kvm-s390-next-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2021-04-17T12:29:41Z

KVM: s390: Fix potential crash in preemptible kernels There is a potential race for preemptible kernels, where the host kernel would get a fault when it is preempted as the wrong point in time.

Merge tag 'kvm-s390-next-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2021-04-15T17:02:13Z

KVM: s390: Updates for 5.13 - properly handle MVPG in nesting KVM (vsie) - allow to forward the yield_to hypercall (diagnose 9c) - fixes

KVM: s390: fix guarded storage control register handling

2021-04-15T13:35:38Z

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

KVM: s390: VSIE: fix MVPG handling for prefixing and MSO

2021-03-24T09:31:55Z

Prefixing needs to be applied to the guest real address to translate it into a guest absolute address. The value of MSO needs to be added to a guest-absolute address in order to obtain the host-virtual. Fixes: bdf7509bbefa ("s390/kvm: VSIE: correctly handle MVPG when in VSIE") Reported-by: Janosch Frank Signed-off-by: Claudio Imbrenda Reviewed-by: David Hildenbrand Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210322140559.500716-3-imbrenda@linux.ibm.com [borntraeger@de.ibm.com simplify mso] Signed-off-by: Christian Borntraeger

KVM: s390: split kvm_s390_real_to_abs

2021-03-24T09:30:30Z

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

KVM: s390: VSIE: correctly handle MVPG when in VSIE

2021-03-24T09:30:29Z

Correctly handle the MVPG instruction when issued by a VSIE guest. Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested virtualization") Cc: stable@vger.kernel.org # f85f1baaa189: KVM: s390: split kvm_s390_logical_to_effective Signed-off-by: Claudio Imbrenda Acked-by: Janosch Frank Reviewed-by: David Hildenbrand Acked-by: Christian Borntraeger Link: https://lore.kernel.org/r/20210302174443.514363-4-imbrenda@linux.ibm.com [borntraeger@de.ibm.com: apply fixup from Claudio] Signed-off-by: Christian Borntraeger