Re: [PATCH v3 3/3] vdpa: Check for iova range at mappings changes

On Thu, Oct 14, 2021 at 4:08 PM Eugenio Perez Martin
[off-list ref] wrote:

On Thu, Oct 14, 2021 at 9:02 AM Jason Wang [off-list ref] wrote:

quoted

On Thu, Oct 14, 2021 at 1:57 PM Eugenio Perez Martin
[off-list ref] wrote:

quoted

On Thu, Oct 14, 2021 at 5:30 AM Jason Wang [off-list ref] wrote:

quoted

On Tue, Oct 12, 2021 at 10:07 PM Eugenio Pérez [off-list ref] wrote:

quoted

Check vdpa device range before updating memory regions so we don't add
any outside of it, and report the invalid change if any.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  2 ++
 hw/virtio/vhost-vdpa.c         | 62 +++++++++++++++++++++++++---------
 hw/virtio/trace-events         |  1 +
 3 files changed, 49 insertions(+), 16 deletions(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index a8963da2d9..c288cf7ecb 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h

@@ -13,6 +13,7 @@
 #define HW_VIRTIO_VHOST_VDPA_H

 #include "hw/virtio/virtio.h"
+#include "standard-headers/linux/vhost_types.h"

 typedef struct VhostVDPAHostNotifier {
     MemoryRegion mr;

@@ -24,6 +25,7 @@ typedef struct vhost_vdpa {
     uint32_t msg_type;
     bool iotlb_batch_begin_sent;
     MemoryListener listener;
+    struct vhost_vdpa_iova_range iova_range;
     struct vhost_dev *dev;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index be7c63b4ba..dbf773d032 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c

@@ -37,20 +37,34 @@ static Int128 vhost_vdpa_section_end(const MemoryRegionSection *section)
     return llend;
 }

-static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section)
-{
-    return (!memory_region_is_ram(section->mr) &&
-            !memory_region_is_iommu(section->mr)) ||
-            memory_region_is_protected(section->mr) ||
-           /* vhost-vDPA doesn't allow MMIO to be mapped  */
-            memory_region_is_ram_device(section->mr) ||
-           /*
-            * Sizing an enabled 64-bit BAR can cause spurious mappings to
-            * addresses in the upper part of the 64-bit address space.  These
-            * are never accessed by the CPU and beyond the address width of
-            * some IOMMU hardware.  TODO: VDPA should tell us the IOMMU width.
-            */
-           section->offset_within_address_space & (1ULL << 63);

[1]

quoted

quoted

+static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section,
+                                                uint64_t iova_min,
+                                                uint64_t iova_max)
+{
+    Int128 llend;
+
+    if ((!memory_region_is_ram(section->mr) &&
+         !memory_region_is_iommu(section->mr)) ||
+        memory_region_is_protected(section->mr) ||
+        /* vhost-vDPA doesn't allow MMIO to be mapped  */
+        memory_region_is_ram_device(section->mr)) {
+        return true;
+    }
+
+    if (section->offset_within_address_space < iova_min) {
+        error_report("RAM section out of device range (min=%lu, addr=%lu)",
+                     iova_min, section->offset_within_address_space);
+        return true;
+    }
+
+    llend = vhost_vdpa_section_end(section);
+    if (int128_gt(llend, int128_make64(iova_max))) {
+        error_report("RAM section out of device range (max=%lu, end addr=%lu)",
+                     iova_max, int128_get64(llend));
+        return true;
+    }
+
+    return false;
 }

 static int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,

@@ -162,7 +176,8 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener,
     void *vaddr;
     int ret;

-    if (vhost_vdpa_listener_skipped_section(section)) {
+    if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
+                                            v->iova_range.last)) {
         return;
     }

@@ -220,7 +235,8 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener,
     Int128 llend, llsize;
     int ret;

-    if (vhost_vdpa_listener_skipped_section(section)) {
+    if (vhost_vdpa_listener_skipped_section(section, v->iova_range.first,
+                                            v->iova_range.last)) {
         return;
     }

@@ -288,6 +304,19 @@ static void vhost_vdpa_add_status(struct vhost_dev *dev, uint8_t status)
     vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &s);
 }

+static void vhost_vdpa_get_iova_range(struct vhost_vdpa *v)
+{
+    int ret = vhost_vdpa_call(v->dev, VHOST_VDPA_GET_IOVA_RANGE,
+                              &v->iova_range);
+    if (ret != 0) {
+        v->iova_range.first = 0;
+        v->iova_range.last = MAKE_64BIT_MASK(0, 63);

Nit:

ULLONG_MAX?

It should be ULLONG_MAX >> 1 to match the previous limit [1],

I think they don't conflict. We just want to preserve the default iova
range as what the kernel did. Kernel will give ULLONG_MAX if
get_iova_range() is not implemented by the device?

Right, so each one understood a different "previous limit" then :). I

Yes.

will replace it with UINT64_MAX if you are ok with that.

Fine with me.

Thanks

Thanks!

quoted

quoted

and
trusting that uint64_t is effectively unsigned long long. I see a 63
bits mask immediately with MAKE_64BIT_MASK (once I remember the
parameter order), but I find it harder to see it with (ULLONG_MAX >>
1).

If you prefer the _MAX options, I would say it is better to stick with
(UINT64_MAX >> 1) or (HWADDR_MAX >> 1), because of this in
CODING_STYLE.rst:

"If you're using "int" or "long", odds are good that there's a better
type. ...", "In the event that you require a specific width, use a
standard type like int32_t, uint32_t, uint64_t, etc", "Use hwaddr for
guest physical addresses".

Does it make sense to you?

If I was not wrong, we can use UINT64_MAX.

Thanks

quoted

Thanks!

quoted

Others look good.

Thanks

quoted

+    }
+
+    trace_vhost_vdpa_get_iova_range(v->dev, v->iova_range.first,
+                                    v->iova_range.last);
+}
+
 static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
 {
     struct vhost_vdpa *v;

@@ -300,6 +329,7 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp)
     v->listener = vhost_vdpa_memory_listener;
     v->msg_type = VHOST_IOTLB_MSG_V2;

+    vhost_vdpa_get_iova_range(v);
     vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE |
                                VIRTIO_CONFIG_S_DRIVER);

diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 8ed19e9d0c..650e521e35 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events

@@ -52,6 +52,7 @@ vhost_vdpa_set_vring_call(void *dev, unsigned int index, int fd) "dev: %p index:
 vhost_vdpa_get_features(void *dev, uint64_t features) "dev: %p features: 0x%"PRIx64
 vhost_vdpa_set_owner(void *dev) "dev: %p"
 vhost_vdpa_vq_get_addr(void *dev, void *vq, uint64_t desc_user_addr, uint64_t avail_user_addr, uint64_t used_user_addr) "dev: %p vq: %p desc_user_addr: 0x%"PRIx64" avail_user_addr: 0x%"PRIx64" used_user_addr: 0x%"PRIx64
+vhost_vdpa_get_iova_range(void *dev, uint64_t first, uint64_t last) "dev: %p first: 0x%"PRIx64" last: 0x%"PRIx64

 # virtio.c
 virtqueue_alloc_element(void *elem, size_t sz, unsigned in_num, unsigned out_num) "elem %p size %zd in_num %u out_num %u"
--

2.27.0

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