Re: [SeaBIOS] [Qemu-devel] [RFC PATCH 6/9] pc: pass paravirt info for hotplug memory slots to BIOS

[Igor Mammedov]

On 04/19/2012 04:08 PM, Vasilis Liaskovitis wrote:
> The numa_fw_cfg paravirt interface is extended to include SRAT information for
>   all hotplug-able memslots. There are 3 words for each hotplug-able memory slot,
>   denoting start address, size and node proximity. nb_numa_nodes is set to 1 by
>   default (not 0), so that we always pass srat info to SeaBIOS.
>
> This information is used by Seabios to build hotplug memory device objects at runtime.
> Signed-off-by: Vasilis Liaskovitis
>
> hw/pc.c |   59 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
>   vl.c    |    4 +++-
>   2 files changed, 56 insertions(+), 7 deletions(-)
>
> diff --git a/hw/pc.c b/hw/pc.c
> index 67f0479..f1f550a 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -46,6 +46,7 @@
>   #include "ui/qemu-spice.h"
>   #include "memory.h"
>   #include "exec-memory.h"
> +#include "memslot.h"
>
> /* output Bochs bios info messages */
>   //#define DEBUG_BIOS
> @@ -592,12 +593,15 @@ int e820_add_entry(uint64_t address, uint64_t length, uint32_t type)
>       return index;
>   }
>
> +static void bochs_bios_setup_hp_memslots(uint64_t *fw_cfg_slots);
>
> static void *bochs_bios_init(void)
> {
>     void *fw_cfg;
>     uint8_t *smbios_table;
>     size_t smbios_len;
>     uint64_t *numa_fw_cfg;
>
> uint64_t *hp_memslots_fw_cfg;
>  int i, j;
>
> register_ioport_write(0x400, 1, 2, bochs_bios_write, NULL);
>
> @@ -630,28 +634,71 @@ static void *bochs_bios_init(void)
>       fw_cfg_add_bytes(fw_cfg, FW_CFG_HPET, (uint8_t *)&hpet_cfg,
>                        sizeof(struct hpet_fw_config));
>       /* allocate memory for the NUMA channel: one (64bit) word for the number
> * of nodes, one word for each VCPU->node and one word for each node to
> * hold the amount of memory.
> * of nodes, one word for the number of hotplug memory slots, one word
> * for each VCPU->node, one word for each node to hold the amount of memory.
> * Finally three words for each hotplug memory slot, denoting start address,
> * size and node proximity.
>  */
> numa_fw_cfg = g_malloc0((1 + max_cpus + nb_numa_nodes) * 8);
> numa_fw_cfg = g_malloc0((2 + max_cpus + nb_numa_nodes + 3 * nb_hp_memslots) * 8);
>  numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
> numa_fw_cfg[1] = cpu_to_le64(nb_hp_memslots);

this will brake compatibility if guest was migrated from old->new qemu
than on reboot it will use old bios that expects numa_fw_cfg[1] to be something else.
Could memslots info be moved to the end of an existing interface?
> for (i = 0; i<  max_cpus; i++) {
>     for (j = 0; j<  nb_numa_nodes; j++) {
>         if (node_cpumask[j]&  (1<<  i)) {
>            numa_fw_cfg[i + 1] = cpu_to_le64(j);
>            numa_fw_cfg[i + 2] = cpu_to_le64(j);
>             break;
>         }
>     }
> }
> for (i = 0; i<  nb_numa_nodes; i++) {
>    numa_fw_cfg[max_cpus + 1 + i] = cpu_to_le64(node_mem[i]);
>    numa_fw_cfg[max_cpus + 2 + i] = cpu_to_le64(node_mem[i]);
> }
> hp_memslots_fw_cfg = numa_fw_cfg + 2 + max_cpus + nb_numa_nodes;
> if (nb_hp_memslots)
>    bochs_bios_setup_hp_memslots(hp_memslots_fw_cfg);
> fw_cfg_add_bytes(fw_cfg, FW_CFG_NUMA, (uint8_t *)numa_fw_cfg,
>                 (1 + max_cpus + nb_numa_nodes) * 8);
>                 (2 + max_cpus + nb_numa_nodes + 3 * nb_hp_memslots) * 8);
>
> return fw_cfg;
>
> }
>
> +static void bochs_bios_setup_hp_memslots(uint64_t *fw_cfg_slots)
> +{
> int i = 0;
> Error *err = NULL;
> DeviceState *dev;
> MemSlotState *slot;
> char *type;
> BusState *bus = sysbus_get_default();
> QTAILQ_FOREACH(dev,&bus->children, sibling) {
>    type = object_property_get_str(OBJECT(dev), "type",&err);
>    if (err) {
>        error_free(err);
>        fprintf(stderr, "error getting device type\n");
>        exit(1);
>    }
>    if (!strcmp(type, "memslot")) {
>        if (!dev->id) {
>            error_free(err);
>            fprintf(stderr, "error getting memslot device id\n");
>            exit(1);
>        }
>        if (!strcmp(dev->id, "initialslot")) continue;
>        slot = MEMSLOT(dev);
>        fw_cfg_slots[3 * slot->idx] = cpu_to_le64(slot->start);
>        fw_cfg_slots[3 * slot->idx + 1] = cpu_to_le64(slot->size);
>        fw_cfg_slots[3 * slot->idx + 2] = cpu_to_le64(slot->node);
>        i++;
>    }
> }
> assert(i == nb_hp_memslots);
>
> +}
> static long get_file_size(FILE *f)
> {
>     long where, size;
>
> diff --git a/vl.c b/vl.c
> index ae91a8a..50df453 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3428,8 +3428,10 @@ int main(int argc, char **argv, char **envp)
>   register_savevm_live(NULL, "ram", 0, 4, NULL, ram_save_live, NULL,
>                        ram_load, NULL);
> if (!nb_numa_nodes)
>    nb_numa_nodes = 1;
>
> if (nb_numa_nodes>  0) {
>
> {
>      int i;
>  if (nb_numa_nodes>  MAX_NODES) {

[Qemu-devel] [RFC PATCH 6/9] pc: pass paravirt info for hotplug memory slots to BIOS

[Vasilis Liaskovitis]

On Fri, Apr 20, 2012 at 12:33:57PM +0200, Igor Mammedov wrote:
> On 04/19/2012 04:08 PM, Vasilis Liaskovitis wrote:
> > numa_fw_cfg = g_malloc0((1 + max_cpus + nb_numa_nodes) * 8);
> > numa_fw_cfg = g_malloc0((2 + max_cpus + nb_numa_nodes + 3 * nb_hp_memslots) * 8);
> > numa_fw_cfg[0] = cpu_to_le64(nb_numa_nodes);
> > numa_fw_cfg[1] = cpu_to_le64(nb_hp_memslots);
>
> this will brake compatibility if guest was migrated from old->new qemu
> than on reboot it will use old bios that expects numa_fw_cfg[1] to be something else.
> Could memslots info be moved to the end of an existing interface?

right. The number of memslots can be placed at 1 + max_cpus + nb_numa_nodes,
instead of right after the number of nodes. This way the old layout is preserved,
and all memslot info comes at the end. I will rewrite.

thanks,
- Vasilis