Message ID | 1177689370.4553974.1386669336686.JavaMail.root@redhat.com |
---|---|
State | New |
Headers | show |
On Tue, Dec 10, 2013 at 04:55:36AM -0500, Gal Hammer wrote: > Kevin, > > The patch was verified and it solves the problem on Windows 7 official release as well. Thanks. I pushed this patch to seabios git master. -Kevin > > ----- Original Message ----- > From: "Kevin O'Connor" <kevin@koconnor.net> > To: "Gerd Hoffmann" <kraxel@redhat.com> > Cc: "Gal Hammer" <ghammer@redhat.com>, "seabios" <seabios@seabios.org>, qemu-devel@nongnu.org, "Julian Pidancet" <julian.pidancet@gmail.com> > Sent: Tuesday, December 10, 2013 12:12:51 AM > Subject: Re: [SeaBIOS] [BUG] Windows 7 fails to start with new vgabios binaries > > On Mon, Dec 09, 2013 at 10:57:25AM -0500, Kevin O'Connor wrote: > > On Mon, Dec 09, 2013 at 02:20:59PM +0100, Gerd Hoffmann wrote: > > > On Mo, 2013-12-09 at 14:18 +0200, Gal Hammer wrote: > > > > A Windows 7 (32-bit) VM running with QXL device fails to start with the > > > > new updated vgabios binaries (commit > > > Tracked down to the new vgabios stack switching. With > > > CONFIG_VGA_ALLOCATE_EXTRA_STACK=n everything is fine again. > > > > Ughh. WinXP doesn't have the problem, but I can also reproduce on > > Win7 beta. > > > > I'll change the default for CONFIG_VGA_ALLOCATE_EXTRA_STACK to off. > > I tracked this down further. The problem is the Windows x86 emulator > doesn't correctly handle memory accesses relative to the %esp > register. Julian reported this some time back and we worked around it > then. However, the recent "extra stack" assembler code inserted a few > of these instructions. > > I think the proper fix is to leave CONFIG_VGA_ALLOCATE_EXTRA_STACK on > and use slightly different assembler so as not to aggravate win7. > > I tested the seabios patch below and my win7 beta now boots okay. > > -Kevin > > > --- a/vgasrc/vgaentry.S > +++ b/vgasrc/vgaentry.S > @@ -97,12 +97,9 @@ entry_10_extrastack: > movl %ecx, BREGS_ecx(%eax) > movw %es, BREGS_es(%eax) > movl %esp, BREGS_size+0(%eax) > - movzwl %sp, %esp > movw %ss, BREGS_size+4(%eax) > - movl (%esp), %edx > - movl %edx, BREGS_code(%eax) > - movw 4(%esp), %dx > - movw %dx, BREGS_flags(%eax) > + popl BREGS_code(%eax) > + popw BREGS_flags(%eax) > > movw %ds, %dx // Setup %ss/%esp and call function > movw %dx, %ss
--- a/vgasrc/vgaentry.S +++ b/vgasrc/vgaentry.S @@ -97,12 +97,9 @@ entry_10_extrastack: movl %ecx, BREGS_ecx(%eax) movw %es, BREGS_es(%eax) movl %esp, BREGS_size+0(%eax) - movzwl %sp, %esp movw %ss, BREGS_size+4(%eax) - movl (%esp), %edx - movl %edx, BREGS_code(%eax) - movw 4(%esp), %dx - movw %dx, BREGS_flags(%eax) + popl BREGS_code(%eax) + popw BREGS_flags(%eax) movw %ds, %dx // Setup %ss/%esp and call function movw %dx, %ss