From cfeb9958c8f4f99f08222a47fe42ea73acb41ecc Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Wed, 15 Aug 2012 13:12:20 +0200 Subject: 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: Markus Armbruster Signed-off-by: Blue Swirl (cherry picked from commit e89001f72edde37fb36fa7c964daa1bbeb2eca26) Signed-off-by: Michael Roth --- hw/pc.c | 31 ++++++++++++++++++------------- 1 file changed, 18 insertions(+), 13 deletions(-) diff --git a/hw/pc.c b/hw/pc.c index e81a06c16..6c4b07bbe 100644 --- a/hw/pc.c +++ b/hw/pc.c @@ -344,32 +344,37 @@ 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); -- cgit v1.2.3