Re: [Xen-devel] [PATCH V3] vm_event: Allow subscribing to write events for specific MSR-s

[Tamas K Lengyel <tamas@xxxxxxxxxxxxx>]

On Fri, Apr 15, 2016 at 3:02 AM, Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx> wrote:

Previously, subscribing to MSR write events was an all-or-none
approach, with special cases for introspection MSR-s. This patch
allows the vm_event consumer to specify exactly what MSR-s it is
interested in, and as a side-effect gets rid of the
vmx_introspection_force_enabled_msrs[] special case.
This replaces the previously posted "xen: Filter out MSR write
events" patch.

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>

---
Changes since V2:
 - Bumped XEN_DOMCTL_INTERFACE_VERSION.
 - Introduced struct monitor_msr_bitmap as recommended by Andrew
   Cooper, which allowed removing some pointer arithmetic magic.
 - Removed arch_ prefix from monitor functions, as recommended
   by Tamas Lengyel.
 - Replaced the page allocation code with xzalloc() / xfree() for
   struct monitor_msr_bitmap.
 - Now returning -ENXIO instead of -EINVAL from the monitor
   functions, as recommended by Konrad Rzeszutek Wilk.
---
 tools/libxc/include/xenctrl.h      |  4 +-
 tools/libxc/xc_monitor.c           |  6 +--
 xen/arch/x86/hvm/event.c           |  3 +-
 xen/arch/x86/hvm/hvm.c             |  3 +-
 xen/arch/x86/hvm/vmx/vmcs.c        | 26 ++---------
 xen/arch/x86/hvm/vmx/vmx.c         | 10 ++--
 xen/arch/x86/monitor.c             | 95 +++++++++++++++++++++++++++++++++-----
 xen/arch/x86/vm_event.c            |  9 ++++
 xen/include/asm-x86/domain.h       |  4 +-
 xen/include/asm-x86/hvm/hvm.h      |  8 ++--
 xen/include/asm-x86/hvm/vmx/vmcs.h |  7 ---
 xen/include/asm-x86/monitor.h      |  8 ++++
 xen/include/public/domctl.h        |  5 +-
 13 files changed, 121 insertions(+), 67 deletions(-)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index f5a034a..9698d46 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2183,8 +2183,8 @@ int xc_monitor_get_capabilities(xc_interface *xch, domid_t domain_id,
 int xc_monitor_write_ctrlreg(xc_interface *xch, domid_t domain_id,
                              uint16_t index, bool enable, bool sync,
                              bool onchangeonly);
-int xc_monitor_mov_to_msr(xc_interface *xch, domid_t domain_id, bool enable,
-                          bool extended_capture);
+int xc_monitor_mov_to_msr(xc_interface *xch, domid_t domain_id, uint32_t msr,
+                          bool enable);

 

So my only concern with this approach here is that the MSR index definitions that are supposed to be passed are never exported via a public header, are only defined in asm-x86/msr-index.h. Should that also be moved to be a public header as part of this patch?

Tamas

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