diff options
| author | Alok Kataria <akataria@vmware.com> | 2008-11-03 11:31:28 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-11-03 11:35:57 -0800 |
| commit | 6bdbfe99916398dbb28d83833cc04757110f2738 (patch) | |
| tree | 7783c666ff16ce70022946c070dd058ae2a74989 | |
| parent | 395628ef4ea12ff0748099f145363b5e33c69acb (diff) | |
x86: VMware: Fix vmware_get_tsc code
Impact: Fix possible failure to calibrate the TSC on Vmware near 4 GHz
The current version of the code to get the tsc frequency from
the VMware hypervisor, will be broken on processor with frequency
(4G-1) HZ, because on such processors eax will have UINT_MAX
and that would be legitimate.
We instead check that EBX did change to decide if we were able to
read the frequency from the hypervisor.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | arch/x86/kernel/cpu/vmware.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 2ac4394fcb9..a0905ecfe7d 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -36,7 +36,7 @@ "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \ "0"(VMWARE_HYPERVISOR_MAGIC), \ "1"(VMWARE_PORT_CMD_##cmd), \ - "2"(VMWARE_HYPERVISOR_PORT), "3"(0) : \ + "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ "memory"); static inline int __vmware_platform(void) @@ -53,7 +53,7 @@ static unsigned long __vmware_get_tsc_khz(void) VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); - if (eax == (uint32_t)-1) + if (ebx == UINT_MAX) return 0; tsc_hz = eax | (((uint64_t)ebx) << 32); do_div(tsc_hz, 1000); |