Bastian Blank
2009-Jul-21 10:36 UTC
[Xen-devel] Re: [PATCH] x86: detect use of extended APIC ID for AMD CPUs
On Thu, Jun 04, 2009 at 12:40:16PM +0200, Andreas Herrmann wrote:> Booting a 32-bit kernel on Magny-Cours results in the following panicThis patch breaks Xen really bad. It uses read_pci_config without knowing that there is something accessible. Also read_pci_config does not define fault handlers. | (XEN) traps.c:413:d375 Unhandled general protection fault fault/trap [#13] on VCPU 0 [ec=0000] | (XEN) domain_crash_sync called from entry.S | (XEN) Domain 375 (vcpu#0) crashed on cpu#1: | (XEN) ----[ Xen-3.2-1 x86_64 debug=n Not tainted ]---- | (XEN) CPU: 1 | (XEN) RIP: e033:[<ffffffff80401d6b>] | (XEN) RFLAGS: 0000000000000282 CONTEXT: guest | (XEN) rax: 000000008000c068 rbx: ffffffff80618a40 rcx: 0000000000000068 | (XEN) rdx: 0000000000000cf8 rsi: 000000000000c000 rdi: 0000000000000000 | (XEN) rbp: 0000000000000018 rsp: ffffffff80621eb0 r8: ffffffff80621efc | (XEN) r9: 00000000ffffffff r10: ffffffff80621ef8 r11: 00000000ffffffff | (XEN) r12: ffffffffffffffff r13: ffffffff80621fd8 r14: 0000002040404030 | (XEN) r15: 00000000015bb600 cr0: 000000008005003b cr4: 00000000000006f0 | (XEN) cr3: 00000002077be000 cr2: 000000204316b000 | (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: e02b cs: e033 | (XEN) Guest stack trace from rsp=ffffffff80621eb0: | (XEN) 0000000000000068 00000000ffffffff 0000000000000000 ffffffff80401d6b | (XEN) 000000010000e030 0000000000010082 ffffffff80621ef0 000000000000e02b | (XEN) ffffffff804aeb3a 0000000100000000 0000302800000000 ffffffff805bcb20 | (XEN) ffffffff80651552 0000000000000000 0000000000000000 0000000000fdfd88 | (XEN) ffffffff8064e47c 0000000001fb9000 ffffffff80545875 0000000000000800 | (XEN) 0000000000002c00 ffffffff81fb9000 ffffffff80650026 ffffffff805ca1c0 | ffffffff80401d44 T read_pci_config | ffffffff804aeb41 t early_init_amd I see several ways to fix this: - Define fault handlers for *_pci_config - Check for Xen - Disable early PCI access from Xen if running unpriviledged and check that in either in *_pci_config or early_init_amd Bastian -- Insults are effective only where emotion is present. -- Spock, "Who Mourns for Adonais?" stardate 3468.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2009-Jul-21 16:56 UTC
[Xen-devel] Re: [PATCH] x86: detect use of extended APIC ID for AMD CPUs
On 07/21/09 03:36, Bastian Blank wrote:> On Thu, Jun 04, 2009 at 12:40:16PM +0200, Andreas Herrmann wrote: > >> Booting a 32-bit kernel on Magny-Cours results in the following panic >> > > This patch breaks Xen really bad. It uses read_pci_config without > knowing that there is something accessible. Also read_pci_config does > not define fault handlers. > > | (XEN) traps.c:413:d375 Unhandled general protection fault fault/trap [#13] on VCPU 0 [ec=0000] > | (XEN) domain_crash_sync called from entry.S > | (XEN) Domain 375 (vcpu#0) crashed on cpu#1: > | (XEN) ----[ Xen-3.2-1 x86_64 debug=n Not tainted ]---- > | (XEN) CPU: 1 > | (XEN) RIP: e033:[<ffffffff80401d6b>] > | (XEN) RFLAGS: 0000000000000282 CONTEXT: guest > | (XEN) rax: 000000008000c068 rbx: ffffffff80618a40 rcx: 0000000000000068 > | (XEN) rdx: 0000000000000cf8 rsi: 000000000000c000 rdi: 0000000000000000 > | (XEN) rbp: 0000000000000018 rsp: ffffffff80621eb0 r8: ffffffff80621efc > | (XEN) r9: 00000000ffffffff r10: ffffffff80621ef8 r11: 00000000ffffffff > | (XEN) r12: ffffffffffffffff r13: ffffffff80621fd8 r14: 0000002040404030 > | (XEN) r15: 00000000015bb600 cr0: 000000008005003b cr4: 00000000000006f0 > | (XEN) cr3: 00000002077be000 cr2: 000000204316b000 > | (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: e02b cs: e033 > | (XEN) Guest stack trace from rsp=ffffffff80621eb0: > | (XEN) 0000000000000068 00000000ffffffff 0000000000000000 ffffffff80401d6b > | (XEN) 000000010000e030 0000000000010082 ffffffff80621ef0 000000000000e02b > | (XEN) ffffffff804aeb3a 0000000100000000 0000302800000000 ffffffff805bcb20 > | (XEN) ffffffff80651552 0000000000000000 0000000000000000 0000000000fdfd88 > | (XEN) ffffffff8064e47c 0000000001fb9000 ffffffff80545875 0000000000000800 > | (XEN) 0000000000002c00 ffffffff81fb9000 ffffffff80650026 ffffffff805ca1c0 > > | ffffffff80401d44 T read_pci_config > | ffffffff804aeb41 t early_init_amd > > I see several ways to fix this: > - Define fault handlers for *_pci_config > - Check for Xen > - Disable early PCI access from Xen if running unpriviledged and check > that in either in *_pci_config or early_init_amd > >I assume "d375" is a domU. cpu_has_apic should be false, and this code shouldn''t be running if the CPU has no (visible) apic. Does this work? (Completely untested.) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 28e5f59..e2485b0 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -356,7 +356,7 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c) #endif #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI) /* check CPU config space for extended APIC ID */ - if (c->x86 >= 0xf) { + if (cpu_has_apic && c->x86 >= 0xf) { unsigned int val; val = read_pci_config(0, 24, 0, 0x68); if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18))) J _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Bastian Blank
2009-Jul-22 09:54 UTC
[Xen-devel] Re: [PATCH] x86: detect use of extended APIC ID for AMD CPUs
On Tue, Jul 21, 2009 at 09:56:45AM -0700, Jeremy Fitzhardinge wrote:> Does this work? (Completely untested.)Yes, it works. It just looks like a workaround. Bastian -- Each kiss is as the first. -- Miramanee, Kirk''s wife, "The Paradise Syndrome", stardate 4842.6 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Thomas Gleixner
2009-Jul-22 14:29 UTC
[Xen-devel] Re: [PATCH] x86: detect use of extended APIC ID for AMD CPUs
On Wed, 22 Jul 2009, Bastian Blank wrote:> On Tue, Jul 21, 2009 at 09:56:45AM -0700, Jeremy Fitzhardinge wrote: > > Does this work? (Completely untested.) > > Yes, it works. It just looks like a workaround.No, it looks fine. Jeremy, can you please send it again with a proper changelog. Thanks, tglx _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2009-Jul-22 16:59 UTC
[Xen-devel] [PATCH] x86/amd: don''t probe for extended APIC ID if APICs are disabled
If we''ve logically disabled apics, don''t probe the PCI space
for the
AMD extended APIC ID.
[ Impact: prevent boot crash under Xen. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reported-by: Bastian Blank <bastian@waldi.eu.org>
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 28e5f59..e2485b0 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -356,7 +356,7 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
#endif
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
/* check CPU config space for extended APIC ID */
- if (c->x86 >= 0xf) {
+ if (cpu_has_apic && c->x86 >= 0xf) {
unsigned int val;
val = read_pci_config(0, 24, 0, 0x68);
if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1
<< 18)))
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