Commit e89001f7 authored by Markus Armbruster's avatar Markus Armbruster Committed by Blue Swirl
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pc: Fix RTC CMOS info on RAM for ram_size < 1MiB 



pc_cmos_init() always claims 640KiB base memory, and ram_size - 1MiB
extended memory.  The latter can underflow to "lots of extended
memory".  Fix both, and clean up some.

Note: SeaBIOS currently requires 1MiB of RAM, and doesn't check
whether it got enough.

Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
Signed-off-by: default avatarBlue Swirl <blauwirbel@gmail.com>
parent ff961015

hw/pc.c

+18 −13
Original line number Diff line number Diff line
@@ -338,32 +338,37 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size, 
    /* various important CMOS locations needed by PC/Bochs bios */



    /* memory size */

    val = 640; /* base memory in K */

    /* base memory (first MiB) */

    val = MIN(ram_size / 1024, 640);

    rtc_set_memory(s, 0x15, val);

    rtc_set_memory(s, 0x16, val >> 8);



    val = (ram_size / 1024) - 1024;

    /* extended memory (next 64MiB) */

    if (ram_size > 1024 * 1024) {

        val = (ram_size - 1024 * 1024) / 1024;

    } else {

        val = 0;

    }

    if (val > 65535)

        val = 65535;

    rtc_set_memory(s, 0x17, val);

    rtc_set_memory(s, 0x18, val >> 8);

    rtc_set_memory(s, 0x30, val);

    rtc_set_memory(s, 0x31, val >> 8);



    if (above_4g_mem_size) {

        rtc_set_memory(s, 0x5b, (unsigned int)above_4g_mem_size >> 16);

        rtc_set_memory(s, 0x5c, (unsigned int)above_4g_mem_size >> 24);

        rtc_set_memory(s, 0x5d, (uint64_t)above_4g_mem_size >> 32);

    }



    if (ram_size > (16 * 1024 * 1024))

        val = (ram_size / 65536) - ((16 * 1024 * 1024) / 65536);

    else

    /* memory between 16MiB and 4GiB */

    if (ram_size > 16 * 1024 * 1024) {

        val = (ram_size - 16 * 1024 * 1024) / 65536;

    } else {

        val = 0;

    }

    if (val > 65535)

        val = 65535;

    rtc_set_memory(s, 0x34, val);

    rtc_set_memory(s, 0x35, val >> 8);

    /* memory above 4GiB */

    val = above_4g_mem_size / 65536;

    rtc_set_memory(s, 0x5b, val);

    rtc_set_memory(s, 0x5c, val >> 8);

    rtc_set_memory(s, 0x5d, val >> 16);



    /* set the number of CPU */

    rtc_set_memory(s, 0x5f, smp_cpus - 1);