qemu-kvm/kvm-pci-add-romsize-property.patch

From aee681700e512679981e39928d8709eb226a4a6d Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Wed, 10 Feb 2021 17:04:45 -0300
Subject: [PATCH 10/54] pci: add romsize property

RH-Author: Peter Xu <peterx@redhat.com>
Message-id: <20210210170445.128304-3-peterx@redhat.com>
Patchwork-id: 101041
O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH 2/2] pci: add romsize property
Bugzilla: 1917830
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

From: Paolo Bonzini <pbonzini@redhat.com>

This property can be useful for distros to set up known-good ROM sizes for
migration purposes.  The VM will fail to start if the ROM is too large,
and migration compatibility will not be broken if the ROM is too small.

Note that even though romsize is a uint32_t, it has to be between 1
(because empty ROM files are not accepted, and romsize must be greater
than the file) and 2^31 (because values above are not powers of two and
are rejected).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201218182736.1634344-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210203131828.156467-3-pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Edmondson <david.edmondson@oracle.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
(cherry picked from commit 08b1df8ff463e72b0875538fb991d5393047606c)
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Eduardo Lima (Etrunko) <etrunko@redhat.com>
---
 hw/pci/pci.c             | 19 +++++++++++++++++--
 hw/xen/xen_pt_load_rom.c | 14 ++++++++++++--
 include/hw/pci/pci.h     |  1 +
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index e4caad33c5..9619b8d068 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -67,6 +67,7 @@ static void pcibus_reset(BusState *qbus);
 static Property pci_props[] = {
     DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
     DEFINE_PROP_STRING("romfile", PCIDevice, romfile),
+    DEFINE_PROP_UINT32("romsize", PCIDevice, romsize, -1),
     DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
     DEFINE_PROP_BIT("multifunction", PCIDevice, cap_present,
                     QEMU_PCI_CAP_MULTIFUNCTION_BITNR, false),
@@ -2106,6 +2107,11 @@ static void pci_qdev_realize(DeviceState *qdev, Error **errp)
     bool is_default_rom;
     uint16_t class_id;
 
+    if (pci_dev->romsize != -1 && !is_power_of_2(pci_dev->romsize)) {
+        error_setg(errp, "ROM size %u is not a power of two", pci_dev->romsize);
+        return;
+    }
+
     /* initialize cap_present for pci_is_express() and pci_config_size(),
      * Note that hybrid PCIs are not set automatically and need to manage
      * QEMU_PCI_CAP_EXPRESS manually */
@@ -2371,7 +2377,16 @@ static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom,
         g_free(path);
         return;
     }
-    size = pow2ceil(size);
+    if (pdev->romsize != -1) {
+        if (size > pdev->romsize) {
+            error_setg(errp, "romfile \"%s\" (%u bytes) is too large for ROM size %u",
+                       pdev->romfile, (uint32_t)size, pdev->romsize);
+            g_free(path);
+            return;
+        }
+    } else {
+        pdev->romsize = pow2ceil(size);
+    }
 
     vmsd = qdev_get_vmsd(DEVICE(pdev));
 
@@ -2381,7 +2396,7 @@ static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom,
         snprintf(name, sizeof(name), "%s.rom", object_get_typename(OBJECT(pdev)));
     }
     pdev->has_rom = true;
-    memory_region_init_rom(&pdev->rom, OBJECT(pdev), name, size, &error_fatal);
+    memory_region_init_rom(&pdev->rom, OBJECT(pdev), name, pdev->romsize, &error_fatal);
     ptr = memory_region_get_ram_ptr(&pdev->rom);
     if (load_image_size(path, ptr, size) < 0) {
         error_setg(errp, "failed to load romfile \"%s\"", pdev->romfile);
diff --git a/hw/xen/xen_pt_load_rom.c b/hw/xen/xen_pt_load_rom.c
index a50a80837e..03422a8a71 100644
--- a/hw/xen/xen_pt_load_rom.c
+++ b/hw/xen/xen_pt_load_rom.c
@@ -53,10 +53,20 @@ void *pci_assign_dev_load_option_rom(PCIDevice *dev,
     }
     fseek(fp, 0, SEEK_SET);
 
+    if (dev->romsize != -1) {
+        if (st.st_size > dev->romsize) {
+            error_report("ROM BAR \"%s\" (%ld bytes) is too large for ROM size %u",
+                         rom_file, (long) st.st_size, dev->romsize);
+            goto close_rom;
+        }
+    } else {
+        dev->romsize = st.st_size;
+    }
+
     snprintf(name, sizeof(name), "%s.rom", object_get_typename(owner));
-    memory_region_init_ram(&dev->rom, owner, name, st.st_size, &error_abort);
+    memory_region_init_ram(&dev->rom, owner, name, dev->romsize, &error_abort);
     ptr = memory_region_get_ram_ptr(&dev->rom);
-    memset(ptr, 0xff, st.st_size);
+    memset(ptr, 0xff, dev->romsize);
 
     if (!fread(ptr, 1, st.st_size, fp)) {
         error_report("pci-assign: Cannot read from host %s", rom_file);
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 72ce649eee..75a6b15757 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -343,6 +343,7 @@ struct PCIDevice {
 
     /* Location of option rom */
     char *romfile;
+    uint32_t romsize;
     bool has_rom;
     MemoryRegion rom;
     uint32_t rom_bar;
-- 
2.27.0