| Message ID | 4E5BB532.4010106@siemens.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Aug 29, 2011 at 05:50:10PM +0200, Jan Kiszka wrote: > QEMU does not provide a HPET block if it was configured with -no-hpet, > other machines SeaBIOS runs on may lack a HPET as well. Perform basic > checks the ID register for a reasonable vendor ID and a clock period > within the valid range, do not build the HPET table if that fails. It looks okay to me. BTW, any particular reason to use 0x05F5E100 instead of 100000000? -Kevin
On 2011-08-30 02:35, Kevin O'Connor wrote: > On Mon, Aug 29, 2011 at 05:50:10PM +0200, Jan Kiszka wrote: >> QEMU does not provide a HPET block if it was configured with -no-hpet, >> other machines SeaBIOS runs on may lack a HPET as well. Perform basic >> checks the ID register for a reasonable vendor ID and a clock period >> within the valid range, do not build the HPET table if that fails. > > It looks okay to me. > > BTW, any particular reason to use 0x05F5E100 instead of 100000000? No, I just blindly grabbed the first number I found in the spec. You may change if you like on commit. Jan
diff --git a/src/acpi.c b/src/acpi.c index ea7b171..29160f4 100644 --- a/src/acpi.c +++ b/src/acpi.c @@ -158,6 +158,9 @@ struct acpi_20_hpet { } PACKED; #define ACPI_HPET_ADDRESS 0xFED00000UL +#define HPET_ID 0x000 +#define HPET_PERIOD 0x004 + /* * SRAT (NUMA topology description) table */ @@ -464,7 +467,16 @@ build_ssdt(void) static void* build_hpet(void) { - struct acpi_20_hpet *hpet = malloc_high(sizeof(*hpet)); + struct acpi_20_hpet *hpet; + const void *hpet_base = (void *)ACPI_HPET_ADDRESS; + u32 hpet_vendor = readl(hpet_base + HPET_ID) >> 16; + u32 hpet_period = readl(hpet_base + HPET_PERIOD); + + if (hpet_vendor == 0 || hpet_vendor == 0xffff || + hpet_period == 0 || hpet_period > 0x05F5E100) + return NULL; + + hpet = malloc_high(sizeof(*hpet)); if (!hpet) { warn_noalloc(); return NULL;
QEMU does not provide a HPET block if it was configured with -no-hpet, other machines SeaBIOS runs on may lack a HPET as well. Perform basic checks the ID register for a reasonable vendor ID and a clock period within the valid range, do not build the HPET table if that fails. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> --- This allows to postpone the hpet_fw_cfg vs. ACPI discussion until we have >1 HPET blocks and/or put them at non-standard addresses. src/acpi.c | 14 +++++++++++++- 1 files changed, 13 insertions(+), 1 deletions(-)