Attachment 886593 Details for Bug 1027565 – proposed patch (downstream only), v2; approach #2

[patch] proposed patch (downstream only), v2; approach #2

0001-qemu_loadvm_state-shadow-SeaBIOS-for-VM-incoming-fro.patch (text/plain), 4.83 KB, created by Laszlo Ersek on 2014-04-15 18:15:42 UTC

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Creator: Laszlo Ersek

Created: 2014-04-15 18:15:42 UTC

Size: 4.83 KB

patch

obsolete

>From 6ed9b4abf927d32910acbe23586b7fb64618501e Mon Sep 17 00:00:00 2001
>From: Laszlo Ersek <lersek@redhat.com>
>Date: Sun, 13 Apr 2014 09:04:49 +0200
>Subject: [RHEL-7.0 qemu-kvm PATCH v2] qemu_loadvm_state(): shadow SeaBIOS for
> VM incoming from RHEL-6 host
>
>SeaBIOS's shadowing logic has no effect on "pc.ram" (only on "pc.bios" and
>"pc.rom") when it runs on the RHEL-6 emulator. When such a guest is
>migrated to the RHEL-7 emulator, where the PAM registers actually work,
>these two UMBs under 1MB simply disappear from the guest's view, breaking
>reboot and S3 resume.
>
>Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>---
>
>Notes:
>    Changes in v2:
>    - print message to stderr when we shadow the UMBs manually [Dave]
>    - also copy C and D segments from pc.rom to pc.ram
>    - move to qemu_loadvm_state() from ram_load() -- we must shadow only
>      when all RAMBlocks have been loaded
>
> include/sysemu/sysemu.h |  1 +
> hw/i386/pc_piix.c       |  1 +
> savevm.c                | 66 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 68 insertions(+)
>
>diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
>index 8dc0a4c..07181ac 100644
>--- a/include/sysemu/sysemu.h
>+++ b/include/sysemu/sysemu.h
>@@ -84,6 +84,7 @@ void qemu_savevm_state_complete(QEMUFile *f);
> void qemu_savevm_state_cancel(void);
> uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size);
> int qemu_loadvm_state(QEMUFile *f);
>+extern bool shadow_bios_after_incoming;
> 
> /* SLIRP */
> void do_info_slirp(Monitor *mon);
>diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
>index 940816f..fea98b6 100644
>--- a/hw/i386/pc_piix.c
>+++ b/hw/i386/pc_piix.c
>@@ -954,6 +954,7 @@ static void pc_compat_rhel650(QEMUMachineInitArgs *args)
>     rom_file_has_mr = false; 
>     has_acpi_build = false;
>     gigabyte_align = false;
>+    shadow_bios_after_incoming = true;
> }
> 
> static void pc_init_rhel650(QEMUMachineInitArgs *args)
>diff --git a/savevm.c b/savevm.c
>index 4d92a7b..6efbb75 100644
>--- a/savevm.c
>+++ b/savevm.c
>@@ -52,6 +52,8 @@
> #define ARP_PTYPE_IP 0x0800
> #define ARP_OP_REQUEST_REV 0x3
> 
>+bool shadow_bios_after_incoming;
>+
> static int announce_self_create(uint8_t *buf,
> 				uint8_t *mac_addr)
> {
>@@ -2195,6 +2197,63 @@ typedef struct LoadStateEntry {
>     int version_id;
> } LoadStateEntry;
> 
>+static void shadow_bios(void)
>+{
>+    RAMBlock *block, *ram, *oprom, *bios;
>+    size_t one_meg, oprom_size, bios_size;
>+    uint8_t *cd_seg_host, *ef_seg_host;
>+
>+    ram = NULL;
>+    oprom = NULL;
>+    bios = NULL;
>+    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
>+        if (strcmp("pc.ram", block->idstr) == 0) {
>+            assert(ram == NULL);
>+            ram = block;
>+        } else if (strcmp("pc.rom", block->idstr) == 0) {
>+            assert(oprom == NULL);
>+            oprom = block;
>+        } else if (strcmp("pc.bios", block->idstr) == 0) {
>+            assert(bios == NULL);
>+            bios = block;
>+        }
>+    }
>+    assert(ram != NULL);
>+    assert(oprom != NULL);
>+    assert(bios != NULL);
>+    assert(memory_region_is_ram(ram->mr));
>+    assert(memory_region_is_ram(oprom->mr));
>+    assert(memory_region_is_ram(bios->mr));
>+    assert(int128_eq(ram->mr->size, int128_make64(ram->length)));
>+    assert(int128_eq(oprom->mr->size, int128_make64(oprom->length)));
>+    assert(int128_eq(bios->mr->size, int128_make64(bios->length)));
>+
>+    one_meg = 1024 * 1024;
>+    oprom_size = 128 * 1024;
>+    bios_size = 128 * 1024;
>+    assert(ram->length >= one_meg);
>+    assert(oprom->length == oprom_size);
>+    assert(bios->length == bios_size);
>+
>+    ef_seg_host = memory_region_get_ram_ptr(ram->mr) + (one_meg - bios_size);
>+    cd_seg_host = ef_seg_host - oprom_size;
>+
>+    /* This is a crude hack, but we must distinguish a rhel6.x.0 machtype guest
>+     * coming in from a RHEL-6 emulator (where shadowing has had no effect on
>+     * "pc.ram") from a similar guest coming in from a RHEL-7 emulator (where
>+     * shadowing has worked). In the latter case we must not trample the live
>+     * SeaBIOS variables in "pc.ram".
>+     */
>+    if (buffer_is_zero(ef_seg_host, bios_size)) {
>+        fprintf(stderr, "copying E and F segments from pc.bios to pc.ram\n");
>+        memcpy(ef_seg_host, memory_region_get_ram_ptr(bios->mr), bios_size);
>+    }
>+    if (buffer_is_zero(cd_seg_host, oprom_size)) {
>+        fprintf(stderr, "copying C and D segments from pc.rom to pc.ram\n");
>+        memcpy(cd_seg_host, memory_region_get_ram_ptr(oprom->mr), oprom_size);
>+    }
>+}
>+
> int qemu_loadvm_state(QEMUFile *f)
> {
>     QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
>@@ -2297,6 +2356,13 @@ int qemu_loadvm_state(QEMUFile *f)
>         }
>     }
> 
>+    /* Supplement SeaBIOS's shadowing now, because it was useless when the
>+     * incoming VM started on the RHEL-6 emulator.
>+     */
>+    if (shadow_bios_after_incoming) {
>+        shadow_bios();
>+    }
>+
>     cpu_synchronize_all_post_init();
> 
>     ret = 0;
>-- 
>1.8.3.1
>

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Attachments on bug 1027565: 885244 | 885245 | 885252 | 885649 | 885650 | 885795 | 885838 | 886494 | 886593 | 886840 | 886841 | 886964 | 888022 | 888273