On 13/12/17 00:42, Maran Wilson wrote: > For certain applications it is desirable to rapidly boot a KVM virtual > machine. In cases where legacy hardware and software support within the > guest is not needed, Qemu should be able to boot directly into the > uncompressed Linux kernel binary without the need to run firmware. > > There already exists an ABI to allow this for Xen PVH guests and the ABI > is supported by Linux and FreeBSD: > > https://xenbits.xen.org/docs/unstable/misc/pvh.html > > This patch enables Qemu to use that same entry point for booting KVM > guests. I'm fine with the general idea. I'm wondering whether you really want to require CONFIG_XEN for the KVM case, though. Wouldn't it be better to rename arch/x86/xen/enlighten_pvh.c to arch/x86/pvh.c and arch/x86/xen/xen-pvh.S to arch/x86/pvh-head.S, put both under CONFIG_PVH umbrella and select this from CONFIG_XEN_PVH and KVM_PVH (or what you like to call it)? In the two moved source files you can make Xen/KVM-specific parts optional via their CONFIG_ options. And you might want to add an own ELF note for the KVM case? > --- > arch/x86/xen/enlighten_pvh.c | 51 +++++++++++++++++++++++++++++++------------- > 1 file changed, 36 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c > index 98ab176..12f3716 100644 > --- a/arch/x86/xen/enlighten_pvh.c > +++ b/arch/x86/xen/enlighten_pvh.c > @@ -31,21 +31,38 @@ static void xen_pvh_arch_setup(void) > acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM; > } > > -static void __init init_pvh_bootparams(void) > +static void __init init_pvh_bootparams(bool xen_guest) > { > struct xen_memory_map memmap; > int rc; > > memset(&pvh_bootparams, 0, sizeof(pvh_bootparams)); > > - memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table); > - set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table); > - rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap); > - if (rc) { > - xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc); > + if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) { > + struct hvm_memmap_table_entry *ep; > + int i; > + > + ep = __va(pvh_start_info.memmap_paddr); > + pvh_bootparams.e820_entries = pvh_start_info.memmap_entries; > + > + for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) { > + pvh_bootparams.e820_table[i].addr = ep->addr; > + pvh_bootparams.e820_table[i].size = ep->size; > + pvh_bootparams.e820_table[i].type = ep->type; > + } > + } else if (xen_guest) { > + memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table); > + set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table); > + rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap); > + if (rc) { > + xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc); > + BUG(); > + } > + pvh_bootparams.e820_entries = memmap.nr_entries; > + } else { > + xen_raw_printk("Error: Could not find memory map\n"); xen_raw_printk() without being a Xen guest? Juergen
