From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 2/3] QEMU/KVM: BIOS: revert TSC zeroing
Date: Mon, 08 Dec 2008 23:12:49 -0200
Message-ID: <20081209012212.093152663@localhost.localdomain>
References: <20081209011247.570596925@localhost.localdomain>
Cc: kvm@vger.kernel.org, Benjamin Serebrin <benjamin.serebrin@amd.com>,
	Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
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Content-Disposition: inline; filename=bios-tsc-fix
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The TSC is zeroed at RESET, and not at SMP initialization.

This avoids the TSC from going out of sync between vcpu's on SMP 
guests.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm-userspace.tip/bios/rombios32.c
===================================================================
--- kvm-userspace.tip.orig/bios/rombios32.c
+++ kvm-userspace.tip/bios/rombios32.c
@@ -610,12 +610,6 @@ void smp_probe(void)
         writel(APIC_BASE + APIC_ICR_LOW, 0x000C4500);
         sipi_vector = AP_BOOT_ADDR >> 12;
         writel(APIC_BASE + APIC_ICR_LOW, 0x000C4600 | sipi_vector);
-	asm volatile(
-		     "xor %%eax, %%eax \n\t"
-		     "xor %%edx, %%edx \n\t"
-		     "mov $0x10, %%ecx \n\t"
-		     "wrmsr"
-		     : : : "eax", "ecx", "edx");
 
 #ifndef BX_QEMU
         delay_ms(10);
Index: kvm-userspace.tip/bios/rombios32start.S
===================================================================
--- kvm-userspace.tip.orig/bios/rombios32start.S
+++ kvm-userspace.tip/bios/rombios32start.S
@@ -43,10 +43,6 @@ smp_ap_boot_code_start:
   cli
   xor %ax, %ax
   mov %ax, %ds
-  xor %eax, %eax
-  xor %edx, %edx
-  mov $0x10, %ecx
-  wrmsr
 
   mov $SMP_MSR_ADDR, %ebx
 11:

--