linux-dev/arch/s390/kvm/intercept.c, branch linus/master

KVM: s390: Honor storage keys when accessing guest memory

2022-02-14T15:12:57Z

Storage key checking had not been implemented for instructions emulated by KVM. Implement it by enhancing the functions used for guest access, in particular those making use of access_guest which has been renamed to access_guest_with_key. Accesses via access_guest_real should not be key checked. For actual accesses, key checking is done by copy_from/to_user_key (which internally uses MVCOS/MVCP/MVCS). In cases where accessibility is checked without an actual access, this is performed by getting the storage key and checking if the access key matches. In both cases, if applicable, storage and fetch protection override are honored. Signed-off-by: Janis Schoetterl-Glausch Reviewed-by: Janosch Frank Reviewed-by: Christian Borntraeger Link: https://lore.kernel.org/r/20220211182215.2730017-3-scgl@linux.ibm.com Signed-off-by: Christian Borntraeger

KVM: s390: pv: avoid stalls when making pages secure

2021-10-25T07:20:39Z

Improve make_secure_pte to avoid stalls when the system is heavily overcommitted. This was especially problematic in kvm_s390_pv_unpack, because of the loop over all pages that needed unpacking. Due to the locks being held, it was not possible to simply replace uv_call with uv_call_sched. A more complex approach was needed, in which uv_call is replaced with __uv_call, which does not loop. When the UVC needs to be executed again, -EAGAIN is returned, and the caller (or its caller) will try again. When -EAGAIN is returned, the path is the same as when the page is in writeback (and the writeback check is also performed, which is harmless). Fixes: 214d9bbcd3a672 ("s390/mm: provide memory management functions for protected KVM guests") Signed-off-by: Claudio Imbrenda Reviewed-by: Janosch Frank Reviewed-by: Christian Borntraeger Link: https://lore.kernel.org/r/20210920132502.36111-5-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger

KVM: s390: Function documentation fixes

2021-09-28T15:56:54Z

The latest compile changes pointed us to a few instances where we use the kernel documentation style but don't explain all variables or don't adhere to it 100%. It's easy to fix so let's do that. Signed-off-by: Janosch Frank Signed-off-by: Christian Borntraeger

KVM: s390: Add memcg accounting to KVM allocations

2020-12-10T12:36:05Z

Almost all kvm allocations in the s390x KVM code can be attributed to the process that triggers the allocation (in other words, no global allocation for other guests). This will help the memcg controller to make the right decisions. Signed-off-by: Christian Borntraeger Acked-by: Janosch Frank Acked-by: Cornelia Huck

Merge tag 'kvm-s390-next-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

2020-03-16T17:19:34Z

KVM: s390: Features and Enhancements for 5.7 part1 1. Allow to disable gisa 2. protected virtual machines Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's state like guest memory and guest registers anymore. Instead the PVMs are mostly managed by a new entity called Ultravisor (UV), which provides an API, so KVM and the PV can request management actions. PVMs are encrypted at rest and protected from hypervisor access while running. They switch from a normal operation into protected mode, so we can still use the standard boot process to load a encrypted blob and then move it into protected mode. Rebooting is only possible by passing through the unprotected/normal mode and switching to protected again. One mm related patch will go via Andrews mm tree ( mm/gup/writeback: add callbacks for inaccessible pages)

KVM: Remove unnecessary asm/kvm_host.h includes

2020-03-16T16:57:34Z

Remove includes of asm/kvm_host.h from files that already include linux/kvm_host.h to make it more obvious that there is no ordering issue between the two headers. linux/kvm_host.h includes asm/kvm_host.h to pick up architecture specific settings, and this will never change, i.e. including asm/kvm_host.h after linux/kvm_host.h may seem problematic, but in practice is simply redundant. Signed-off-by: Peter Xu Signed-off-by: Paolo Bonzini

KVM: s390: protvirt: Report CPU state to Ultravisor

2020-02-27T18:47:12Z

VCPU states have to be reported to the ultravisor for SIGP interpretation, kdump, kexec and reboot. Signed-off-by: Janosch Frank Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger

KVM: s390: protvirt: Write sthyi data to instruction data area

2020-02-27T18:47:11Z

STHYI data has to go through the bounce buffer. Signed-off-by: Janosch Frank Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger

KVM: s390/mm: handle guest unpin events

2020-02-27T18:47:11Z

The current code tries to first pin shared pages, if that fails (e.g. because the page is not shared) it will export them. For shared pages this means that we get a new intercept telling us that the guest is unsharing that page. We will unpin the page at that point in time, following the same rules as for making a page secure (i.e. waiting for writeback, no elevated page references, etc.) Signed-off-by: Claudio Imbrenda Acked-by: David Hildenbrand Reviewed-by: Cornelia Huck [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger

KVM: s390: protvirt: handle secure guest prefix pages

2020-02-27T18:47:11Z

The SPX instruction is handled by the ultravisor. We do get a notification intercept, though. Let us update our internal view. In addition to that, when the guest prefix page is not secure, an intercept 112 (0x70) is indicated. Let us make the prefix pages secure again. Signed-off-by: Janosch Frank Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger