linux-stable/Documentation/virt/kvm
David Woodhouse d8ba8ba4c8 KVM: x86/xen: Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured
Closer inspection of the Xen code shows that we aren't supposed to be
using the XEN_RUNSTATE_UPDATE flag unconditionally. It should be
explicitly enabled by guests through the HYPERVISOR_vm_assist hypercall.
If we randomly set the top bit of ->state_entry_time for a guest that
hasn't asked for it and doesn't expect it, that could make the runtimes
fail to add up and confuse the guest. Without the flag it's perfectly
safe for a vCPU to read its own vcpu_runstate_info; just not for one
vCPU to read *another's*.

I briefly pondered adding a word for the whole set of VMASST_TYPE_*
flags but the only one we care about for HVM guests is this, so it
seemed a bit pointless.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221127122210.248427-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-30 10:59:37 -05:00
..
arm arm64: Rename the VHE switch to "finalise_el2" 2022-07-01 15:22:51 +01:00
devices KVM: s390: pv: don't allow userspace to set the clock under PV 2022-11-07 10:14:15 +01:00
s390 ARM: 2022-08-04 14:59:54 -07:00
x86 This update includes the following changes: 2022-10-10 13:04:25 -07:00
api.rst KVM: x86/xen: Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured 2022-11-30 10:59:37 -05:00
index.rst Documentation: KVM: add separate directories for architecture-specific documentation 2022-03-29 13:21:20 -04:00
locking.rst Documentation: kvm: include new locks 2022-03-29 13:21:19 -04:00
ppc-pv.rst docs: kvm: Convert ppc-pv.txt to ReST format 2020-02-12 20:10:05 +01:00
review-checklist.rst docs: fix broken references for ReST files that moved around 2020-04-20 15:45:03 -06:00
vcpu-requests.rst KVM: remove KVM_REQ_UNHALT 2022-09-26 12:37:21 -04:00