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Re: [Qemu-devel] [PATCH v3 2/2] Xen: Use the ioreq-server API when avail
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/2] Xen: Use the ioreq-server API when available |
Date: |
Wed, 15 Oct 2014 15:37:53 +0100 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Wed, 15 Oct 2014, Paul Durrant wrote:
> The ioreq-server API added to Xen 4.5 offers better security than
> the existing Xen/QEMU interface because the shared pages that are
> used to pass emulation request/results back and forth are removed
> from the guest's memory space before any requests are serviced.
> This prevents the guest from mapping these pages (they are in a
> well known location) and attempting to attack QEMU by synthesizing
> its own request structures. Hence, this patch modifies configure
> to detect whether the API is available, and adds the necessary
> code to use the API if it is.
>
> Signed-off-by: Paul Durrant <address@hidden>
The patch is OK, so you can add my Acked-by.
I have a couple of minor comments below. If you need to repost it then
would be nice if you could address them.
> Cc: Stefano Stabellini <address@hidden>
> Cc: Peter Maydell <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Michael Tokarev <address@hidden>
> Cc: Stefan Hajnoczi <address@hidden>
> Cc: Stefan Weil <address@hidden>
> Cc: Olaf Hering <address@hidden>
> Cc: Gerd Hoffmann <address@hidden>
> Cc: Alexey Kardashevskiy <address@hidden>
> Cc: Alexander Graf <address@hidden>
> ---
> configure | 29 ++++++
> include/hw/xen/xen_common.h | 222
> +++++++++++++++++++++++++++++++++++++++++++
> trace-events | 8 ++
> xen-hvm.c | 174 +++++++++++++++++++++++++++++----
> 4 files changed, 412 insertions(+), 21 deletions(-)
>
[...]
> diff --git a/xen-hvm.c b/xen-hvm.c
> index 05e522c..0bbbf2a 100644
> --- a/xen-hvm.c
> +++ b/xen-hvm.c
> @@ -62,9 +62,6 @@ static inline ioreq_t *xen_vcpu_ioreq(shared_iopage_t
> *shared_page, int vcpu)
> }
> # define FMT_ioreq_size "u"
> #endif
> -#ifndef HVM_PARAM_BUFIOREQ_EVTCHN
> -#define HVM_PARAM_BUFIOREQ_EVTCHN 26
> -#endif
>
> #define BUFFER_IO_MAX_DELAY 100
>
> @@ -78,6 +75,7 @@ typedef struct XenPhysmap {
> } XenPhysmap;
>
> typedef struct XenIOState {
> + ioservid_t ioservid;
> shared_iopage_t *shared_page;
> buffered_iopage_t *buffered_io_page;
> QEMUTimer *buffered_io_timer;
> @@ -92,6 +90,8 @@ typedef struct XenIOState {
>
> struct xs_handle *xenstore;
> MemoryListener memory_listener;
> + MemoryListener io_listener;
> + DeviceListener device_listener;
> QLIST_HEAD(, XenPhysmap) physmap;
> hwaddr free_phys_offset;
> const XenPhysmap *log_for_dirtybit;
> @@ -442,12 +442,23 @@ static void xen_set_memory(struct MemoryListener
> *listener,
> bool log_dirty = memory_region_is_logging(section->mr);
> hvmmem_type_t mem_type;
>
> + if (section->mr == &ram_memory) {
> + return;
> + } else {
> + if (add) {
> + xen_map_memory_section(xen_xc, xen_domid, state->ioservid,
> + section);
> + } else {
> + xen_unmap_memory_section(xen_xc, xen_domid, state->ioservid,
> + section);
> + }
> + }
> if (!memory_region_is_ram(section->mr)) {
> return;
> }
>
> - if (!(section->mr != &ram_memory
> - && ( (log_dirty && add) || (!log_dirty && !add)))) {
> + if (!(log_dirty && add) && !(!log_dirty && !add)) {
> return;
if (!((log_dirty && add) || (!log_dirty && !add)))
> }
>
> @@ -480,6 +491,7 @@ static void xen_region_add(MemoryListener *listener,
> MemoryRegionSection *section)
> {
> memory_region_ref(section->mr);
> +
> xen_set_memory(listener, section, true);
> }
>
> @@ -487,9 +499,54 @@ static void xen_region_del(MemoryListener *listener,
> MemoryRegionSection *section)
> {
> xen_set_memory(listener, section, false);
> +
> memory_region_unref(section->mr);
> }
Useless changes?
Re: [Qemu-devel] [PATCH v3 2/2] Xen: Use the ioreq-server API when available, Peter Maydell, 2014/10/15