From: Paul Durrant <pdurrant@xxxxxxxxxx>
Currently the shared_info page is treated as guest memory and the VMM
informs KVM of its location using a GFN. However it is not guest memory as
such; it's an overlay page. So the pfncache is pointlessly invalidated and
re-activated to create a new mapping of the *same page* of memory every
time the guest requests that shared_info be mapped into its address space.
Avoid doing that by modifying the pfncache code to allow activation using
a fixed userspace HVA as well as a GPA.
Version 8 of the series has been substantially re-worked and includes
several clean-up patches, particlarly the non-trivial clean-up patches:
"pfncache: remove KVM_GUEST_USES_PFN usage" and "xen: split up
kvm_xen_set_evtchn_fast()". Each patch carries its own version history.
Paul Durrant (15):
KVM: pfncache: Add a map helper function
KVM: pfncache: remove unnecessary exports
KVM: xen: mark guest pages dirty with the pfncache lock held
KVM: pfncache: add a mark-dirty helper
KVM: pfncache: remove KVM_GUEST_USES_PFN usage
KVM: pfncache: stop open-coding offset_in_page()
KVM: pfncache: include page offset in uhva and use it consistently
KVM: pfncache: allow a cache to be activated with a fixed (userspace)
HVA
KVM: xen: allow shared_info to be mapped by fixed HVA
KVM: xen: allow vcpu_info to be mapped by fixed HVA
KVM: selftests / xen: map shared_info using HVA rather than GFN
KVM: selftests / xen: re-map vcpu_info using HVA rather than GPA
KVM: xen: advertize the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA capability
KVM: xen: split up kvm_xen_set_evtchn_fast()
KVM: xen: allow vcpu_info content to be 'safely' copied
Documentation/virt/kvm/api.rst | 53 +++-
arch/x86/kvm/x86.c | 7 +-
arch/x86/kvm/xen.c | 260 +++++++++++-------
include/linux/kvm_host.h | 38 ++-
include/linux/kvm_types.h | 8 -
include/uapi/linux/kvm.h | 9 +-
.../selftests/kvm/x86_64/xen_shinfo_test.c | 59 +++-
virt/kvm/pfncache.c | 175 ++++++------
8 files changed, 374 insertions(+), 235 deletions(-)
base-commit: 45b890f7689eb0aba454fc5831d2d79763781677
---
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
--
2.39.2
