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From 9d150071a8170807a0e5f638e3eddbbc29219ddc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
Date: Wed, 13 Dec 2017 13:38:45 +0100
Subject: [PATCH 14/41] fw_cfg: enable DMA if -device vmcoreinfo
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RH-Author: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: <20171213133912.26176-15-marcandre.lureau@redhat.com>
Patchwork-id: 78364
O-Subject: [RHEL-7.5 qemu-kvm PATCH v3 14/41] fw_cfg: enable DMA if -device vmcoreinfo
Bugzilla: 1411490
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Upstream status: RHEL-only

vmcoreinfo needs fw_cfg with DMA enabled. However, for compatibility
reasons, DMA can't be enabled by default. In order to avoid having a
RHEL-specific libvirt patch to enable DMA when vmcoreinfo device is
requested, it can be done in qemu directly.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/nvram/fw_cfg.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 616c782..7caf43c 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -30,6 +30,7 @@
 #include "trace.h"
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
+#include "qemu/option.h"
 
 #define FW_CFG_CTL_SIZE 2
 #define FW_CFG_DATA_SIZE 1
@@ -675,6 +676,17 @@ static void fw_cfg_machine_ready(struct Notifier *n, void *data)
     fw_cfg_add_file(s, "bootorder", (uint8_t*)bootindex, len);
 }
 
+static int driver_is_vmcoreinfo(QemuOpts *opts, void *opaque)
+{
+    return g_strcmp0(qemu_opt_get(opts, "driver"), "vmcoreinfo") == 0;
+}
+
+static bool opts_has_vmcoreinfo(void)
+{
+    return qemu_opts_foreach(qemu_find_opts("device"),
+                             driver_is_vmcoreinfo, NULL, 1) != 0;
+}
+
 static FWCfgState *
 fw_cfg_init_dma(uint32_t ctl_port, uint32_t data_port,
                 uint32_t dma_port,
@@ -692,6 +704,11 @@ fw_cfg_init_dma(uint32_t ctl_port, uint32_t data_port,
     qdev_prop_set_uint32(dev, "data_iobase", data_port);
     qdev_prop_set_uint32(dev, "dma_iobase", dma_port);
 
+    if (opts_has_vmcoreinfo()) {
+        /* RHEL-only: enable DMA operations for vmcoreinfo device */
+        qdev_prop_set_bit(dev, "dma_enabled", true);
+    }
+
     if (!dma_requested) {
         qdev_prop_set_bit(dev, "dma_enabled", false);
     }
-- 
1.8.3.1