From: Chris Lalancette <clalance@redhat.com>
Date: Fri, 20 Mar 2009 10:22:53 +0100
Subject: [x86] VMware: Fix vmware_get_tsc code
Message-id: 49C3606D.6040006@redhat.com
O-Subject: [RHEL5.4 PATCH 7/14]: x86: VMware: Fix vmware_get_tsc code
Bugzilla: 463573
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Justin M. Forbes <jforbes@redhat.com>

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.

upstream commit 6bdbfe99916398dbb28d83833cc04757110f2738

Fixes BZ 463573

diff --git a/arch/i386/kernel/cpu/vmware.c b/arch/i386/kernel/cpu/vmware.c
index 63fe3b4..f17a461 100644
--- a/arch/i386/kernel/cpu/vmware.c
+++ b/arch/i386/kernel/cpu/vmware.c
@@ -38,7 +38,7 @@
 			"=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)
@@ -55,7 +55,7 @@ static unsigned long __vmware_get_tsc_khz(void)
 
         VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
 
-        if (ebx == (uint32_t)-1)
+        if (ebx == UINT_MAX)
                 return 0;
         tsc_hz = eax | (((uint64_t)ebx) << 32);
         do_div(tsc_hz, 1000);