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From 18238ae670fb38f5ca7002bc8da7b7aa9d612f68 Mon Sep 17 00:00:00 2001
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From: Laszlo Ersek <lersek@redhat.com>
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Date: Sat, 11 Jan 2014 17:59:58 +0100
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Subject: [PATCH 08/22] pc_sysfw: allow flash (-pflash) memory to be used with KVM
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RH-Author: Laszlo Ersek <lersek@redhat.com>
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Message-id: <1389463208-6278-9-git-send-email-lersek@redhat.com>
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Patchwork-id: 56621
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O-Subject: [RHEL-7.0 qemu-kvm PATCH 08/18] pc_sysfw: allow flash (-pflash) memory to be used with KVM
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Bugzilla: 1032346
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Amos Kong <akong@redhat.com>
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RH-Acked-by: Andrew Jones <drjones@redhat.com>
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From: Jordan Justen <jordan.l.justen@intel.com>
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When pc-sysfw.rom_only == 0, flash memory will be
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usable with kvm. In order to enable flash memory mode,
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a pflash device must be created. (For example, by
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using the -pflash command line parameter.)
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Usage of a flash memory device with kvm requires
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KVM_CAP_READONLY_MEM, and kvm will abort if
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a flash device is used with an older kvm which does
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not support this capability.
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If a flash device is not used, then qemu/kvm will
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operate in the original rom-mode.
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Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
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Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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Message-id: 1369816047-16384-5-git-send-email-jordan.l.justen@intel.com
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Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
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(cherry picked from commit dafb82e0fc89b631d25f8def649fbfd14fec3db2)
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Signed-off-by: Laszlo Ersek <lersek@redhat.com>
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---
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 hw/block/pc_sysfw.c | 50 +++++++++++++++++++++++++++++++-------------------
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 1 file changed, 31 insertions(+), 19 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/block/pc_sysfw.c |   50 +++++++++++++++++++++++++++++++-------------------
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 1 files changed, 31 insertions(+), 19 deletions(-)
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diff --git a/hw/block/pc_sysfw.c b/hw/block/pc_sysfw.c
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index 4d82c70..76932fc 100644
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--- a/hw/block/pc_sysfw.c
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+++ b/hw/block/pc_sysfw.c
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@@ -217,28 +217,40 @@ void pc_system_firmware_init(MemoryRegion *rom_memory)
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     qdev_init_nofail(DEVICE(sysfw_dev));
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-    if (sysfw_dev->rom_only) {
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-        old_pc_system_rom_init(rom_memory, sysfw_dev->isapc_ram_fw);
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-        return;
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-    }
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-
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     pflash_drv = drive_get(IF_PFLASH, 0, 0);
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-    /* Currently KVM cannot execute from device memory.
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-       Use old rom based firmware initialization for KVM. */
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-    /*
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-     * This is a Bad Idea, because it makes enabling/disabling KVM
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-     * guest-visible.  Let's fix it for real in QEMU 1.6.
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-     */
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-    if (kvm_enabled()) {
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-        if (pflash_drv != NULL) {
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-            fprintf(stderr, "qemu: pflash cannot be used with kvm enabled\n");
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-            exit(1);
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-        } else {
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-            sysfw_dev->rom_only = 1;
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-            old_pc_system_rom_init(rom_memory, sysfw_dev->isapc_ram_fw);
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-            return;
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+    if (pc_sysfw_flash_vs_rom_bug_compatible) {
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+        /*
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+         * This is a Bad Idea, because it makes enabling/disabling KVM
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+         * guest-visible.  Do it only in bug-compatibility mode.
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+         */
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+        if (kvm_enabled()) {
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+            if (pflash_drv != NULL) {
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+                fprintf(stderr, "qemu: pflash cannot be used with kvm enabled\n");
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+                exit(1);
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+            } else {
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+                /* In old pc_sysfw_flash_vs_rom_bug_compatible mode, we assume
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+                 * that KVM cannot execute from device memory. In this case, we
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+                 * use old rom based firmware initialization for KVM. But, since
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+                 * this is different from non-kvm mode, this behavior is
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+                 * undesirable */
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+                sysfw_dev->rom_only = 1;
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+            }
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         }
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+    } else if (pflash_drv == NULL) {
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+        /* When a pflash drive is not found, use rom-mode */
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+        sysfw_dev->rom_only = 1;
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+    } else if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
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+        /* Older KVM cannot execute from device memory. So, flash memory
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+         * cannot be used unless the readonly memory kvm capability is present. */
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+        fprintf(stderr, "qemu: pflash with kvm requires KVM readonly memory support\n");
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+        exit(1);
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+    }
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+
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+    /* If rom-mode is active, use the old pc system rom initialization. */
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+    if (sysfw_dev->rom_only) {
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+        old_pc_system_rom_init(rom_memory, sysfw_dev->isapc_ram_fw);
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+        return;
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     }
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     /* If a pflash drive is not found, then create one using
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-- 
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1.7.1
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