From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45001) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8WyM-0005aG-GI for qemu-devel@nongnu.org; Wed, 10 May 2017 15:08:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8WyK-0004kP-Lm for qemu-devel@nongnu.org; Wed, 10 May 2017 15:08:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34412) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d8WyK-0004kL-Cu for qemu-devel@nongnu.org; Wed, 10 May 2017 15:08:28 -0400 Date: Wed, 10 May 2017 22:08:25 +0300 From: "Michael S. Tsirkin" Message-ID: <1494443192-17177-6-git-send-email-mst@redhat.com> References: <1494443192-17177-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1494443192-17177-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 5/9] pc/fwcfg: unbreak migration from qemu-2.5 and qemu-2.6 during firmware boot List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Igor Mammedov , Eduardo Habkost , Laszlo Ersek , Paolo Bonzini , Richard Henderson From: Igor Mammedov Since 2.7 commit (b2a575a Add optionrom compatible with fw_cfg DMA version) regressed migration during firmware exection time by abusing fwcfg.dma_enabled property to decide loading dma version of option rom AND by mistake disabling DMA for 2.6 and earlier globally instead of only for option rom. so 2.6 machine type guest is broken when it already runs firmware in DMA mode but migrated to qemu-2.7(pc-2.6) at that time; a) qemu-2.6:pc2.6 (fwcfg.dma=on,firmware=dma,oprom=ioport) b) qemu-2.7:pc2.6 (fwcfg.dma=off,firmware=ioport,oprom=ioport) to: a b from a OK FAIL b OK OK So we currently have broken forward migration from qemu-2.6 to qemu-2.[789] that however could be fixed for 2.10 by re-enabling DMA for 2.[56] machine types and allowing dma capable option rom only since 2.7. As result qemu should end up with: c) qemu-2.10:pc2.6 (fwcfg.dma=on,firmware=dma,oprom=ioport) to: a b c from a OK FAIL OK b OK OK OK c OK FAIL OK where forward migration from qemu-2.6 to qemu-2.10 should work again leaving only qemu-2.[789]:pc-2.6 broken. Reported-by: Eduardo Habkost Analyzed-by: Laszlo Ersek Signed-off-by: Igor Mammedov Reviewed-by: Laszlo Ersek Reviewed-by: Eduardo Habkost Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/i386/pc.h | 7 +++---- hw/i386/pc.c | 9 ++++----- hw/i386/pc_piix.c | 1 + hw/i386/pc_q35.c | 1 + 4 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 416aaa5..d0183c4 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -151,6 +151,9 @@ struct PCMachineClass { bool save_tsc_khz; /* generate legacy CPU hotplug AML */ bool legacy_cpu_hotplug; + + /* use DMA capable linuxboot option rom */ + bool linuxboot_dma_enabled; }; #define TYPE_PC_MACHINE "generic-pc-machine" @@ -438,10 +441,6 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *); #define PC_COMPAT_2_6 \ HW_COMPAT_2_6 \ {\ - .driver = "fw_cfg_io",\ - .property = "dma_enabled",\ - .value = "off",\ - },{\ .driver = TYPE_X86_CPU,\ .property = "cpuid-0xb",\ .value = "off",\ diff --git a/hw/i386/pc.c b/hw/i386/pc.c index f3b372a..8063241 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1047,12 +1047,10 @@ static void load_linux(PCMachineState *pcms, fw_cfg_add_i32(fw_cfg, FW_CFG_SETUP_SIZE, setup_size); fw_cfg_add_bytes(fw_cfg, FW_CFG_SETUP_DATA, setup, setup_size); - if (fw_cfg_dma_enabled(fw_cfg)) { + option_rom[nb_option_roms].bootindex = 0; + option_rom[nb_option_roms].name = "linuxboot.bin"; + if (pcmc->linuxboot_dma_enabled && fw_cfg_dma_enabled(fw_cfg)) { option_rom[nb_option_roms].name = "linuxboot_dma.bin"; - option_rom[nb_option_roms].bootindex = 0; - } else { - option_rom[nb_option_roms].name = "linuxboot.bin"; - option_rom[nb_option_roms].bootindex = 0; } nb_option_roms++; } @@ -2321,6 +2319,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) * to be used at the moment, 32K should be enough for a while. */ pcmc->acpi_data_size = 0x20000 + 0x8000; pcmc->save_tsc_khz = true; + pcmc->linuxboot_dma_enabled = true; mc->get_hotplug_handler = pc_get_hotpug_handler; mc->cpu_index_to_socket_id = pc_cpu_index_to_socket_id; mc->possible_cpu_arch_ids = pc_possible_cpu_arch_ids; diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index 9f102aa..a11190b 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -474,6 +474,7 @@ static void pc_i440fx_2_6_machine_options(MachineClass *m) PCMachineClass *pcmc = PC_MACHINE_CLASS(m); pc_i440fx_2_7_machine_options(m); pcmc->legacy_cpu_hotplug = true; + pcmc->linuxboot_dma_enabled = false; SET_MACHINE_COMPAT(m, PC_COMPAT_2_6); } diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index dd792a8..0a61a20 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -335,6 +335,7 @@ static void pc_q35_2_6_machine_options(MachineClass *m) PCMachineClass *pcmc = PC_MACHINE_CLASS(m); pc_q35_2_7_machine_options(m); pcmc->legacy_cpu_hotplug = true; + pcmc->linuxboot_dma_enabled = false; SET_MACHINE_COMPAT(m, PC_COMPAT_2_6); } -- MST