From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lively Subject: [PATCH] fix for Failed VMEntry on VMX Date: Tue, 02 May 2006 10:58:00 -0400 Message-ID: <44577378.9070303@virtualiron.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------060607070701070805060705" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format. --------------060607070701070805060705 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit I've been getting a "Failed VMEntry" when trying to boot a second VMX guest (while the first one is still running, but is no longer in real mode). This patch fixes it. VMX(assist) uses vm86 in its real mode emulation. Upon vmentry into a guest in vm86 mode, all segment bases must be equal to the corresponding segment selector shifted left four bits. The vmx routine vmx_load_cpu_guest_regs() was loading the segment selectors. Now it makes sure to set the segment bases appropriately if we're in vm86 mode. Tested on 64bit hypervisor with 2 64-bit VMX domUs (on 2-way dom0). Dave --------------060607070701070805060705 Content-Type: text/x-patch; name="failed-vmentry-fix.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="failed-vmentry-fix.patch" Ensure segment bases are consistent with their selectors for VMX guests in VM86 mode. Signed-off-by: David Lively diff -r 880433ba7487 xen/arch/x86/hvm/vmx/vmx.c --- a/xen/arch/x86/hvm/vmx/vmx.c Mon May 1 17:08:02 2006 -0400 +++ b/xen/arch/x86/hvm/vmx/vmx.c Tue May 2 10:31:03 2006 -0400 @@ -487,6 +487,33 @@ static void vmx_store_cpu_guest_regs( __vmptrld(virt_to_maddr(current->arch.hvm_vmx.vmcs)); } +/* Ensure segment bases are consistent with their + * selectors for guests in VM86 mode. + */ +static void fixup_vm86_seg_bases(struct cpu_user_regs *regs) +{ + unsigned long base; + + BUG_ON(__vmread(GUEST_ES_BASE, &base)); + if (regs->es << 4 != base) + BUG_ON(__vmwrite(GUEST_ES_BASE, regs->es << 4)); + BUG_ON(__vmread(GUEST_CS_BASE, &base)); + if (regs->cs << 4 != base) + BUG_ON(__vmwrite(GUEST_CS_BASE, regs->cs << 4)); + BUG_ON(__vmread(GUEST_SS_BASE, &base)); + if (regs->ss << 4 != base) + BUG_ON(__vmwrite(GUEST_SS_BASE, regs->ss << 4)); + BUG_ON(__vmread(GUEST_DS_BASE, &base)); + if (regs->ds << 4 != base) + BUG_ON(__vmwrite(GUEST_DS_BASE, regs->ds << 4)); + BUG_ON(__vmread(GUEST_FS_BASE, &base)); + if (regs->fs << 4 != base) + BUG_ON(__vmwrite(GUEST_FS_BASE, regs->fs << 4)); + BUG_ON(__vmread(GUEST_GS_BASE, &base)); + if (regs->gs << 4 != base) + BUG_ON(__vmwrite(GUEST_GS_BASE, regs->gs << 4)); +} + void vmx_load_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *regs) { if ( v != current ) @@ -523,6 +550,8 @@ void vmx_load_cpu_guest_regs(struct vcpu __vm_set_bit(EXCEPTION_BITMAP, EXCEPTION_BITMAP_DB); else __vm_clear_bit(EXCEPTION_BITMAP, EXCEPTION_BITMAP_DB); + if (regs->rflags & EF_VM) + fixup_vm86_seg_bases(regs); __vmwrite(GUEST_CS_SELECTOR, regs->cs); __vmwrite(GUEST_RIP, regs->rip); @@ -540,6 +569,8 @@ void vmx_load_cpu_guest_regs(struct vcpu __vm_set_bit(EXCEPTION_BITMAP, EXCEPTION_BITMAP_DB); else __vm_clear_bit(EXCEPTION_BITMAP, EXCEPTION_BITMAP_DB); + if (regs->eflags & EF_VM) + fixup_vm86_seg_bases(regs); __vmwrite(GUEST_CS_SELECTOR, regs->cs); __vmwrite(GUEST_RIP, regs->eip); --------------060607070701070805060705 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --------------060607070701070805060705--