pc_sysfw: allow flash (-pflash) memory to be used with KVM
When pc-sysfw.rom_only == 0, flash memory will be usable with kvm. In order to enable flash memory mode, a pflash device must be created. (For example, by using the -pflash command line parameter.) Usage of a flash memory device with kvm requires KVM_CAP_READONLY_MEM, and kvm will abort if a flash device is used with an older kvm which does not support this capability. If a flash device is not used, then qemu/kvm will operate in the original rom-mode. Signed-off-by: Jordan Justen <jordan.l.justen@intel.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1369816047-16384-5-git-send-email-jordan.l.justen@intel.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
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@ -220,29 +220,41 @@ 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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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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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. Let's fix it for real in QEMU 1.6.
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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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/* 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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}
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/* If a pflash drive is not found, then create one using
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the bios filename. */
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