From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
commit 14cb5d83068ecf15d2da6f7d0e9ea9edbcbc0457 upstream.
Xen doesn't offer MSR_FAM10H_MMIO_CONF_BASE to all guests. This results
in the following warning:
unchecked MSR access error: RDMSR from 0xc0010058 at rIP: 0xffffffff8101d19f (xen_do_read_msr+0x7f/0xa0)
Call Trace:
xen_read_msr+0x1e/0x30
amd_get_mmconfig_range+0x2b/0x80
quirk_amd_mmconfig_area+0x28/0x100
pnp_fixup_device+0x39/0x50
__pnp_add_device+0xf/0x150
pnp_add_device+0x3d/0x100
pnpacpi_add_device_handler+0x1f9/0x280
acpi_ns_get_device_callback+0x104/0x1c0
acpi_ns_walk_namespace+0x1d0/0x260
acpi_get_devices+0x8a/0xb0
pnpacpi_init+0x50/0x80
do_one_initcall+0x46/0x2e0
kernel_init_freeable+0x1da/0x2f0
kernel_init+0x16/0x1b0
ret_from_fork+0x30/0x50
ret_from_fork_asm+0x1b/0x30
based on quirks for a "PNP0c01" device. Treating MMCFG as disabled is the
right course of action, so no change is needed there.
This was most likely exposed by fixing the Xen MSR accessors to not be
silently-safe.
Fixes: 3fac3734c43a ("xen/pv: support selecting safe/unsafe msr accesses")
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20250307002846.3026685-1-andrew.cooper3@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/amd_nb.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -342,7 +342,6 @@ bool __init early_is_amd_nb(u32 device)
struct resource *amd_get_mmconfig_range(struct resource *res)
{
- u32 address;
u64 base, msr;
unsigned int segn_busn_bits;
@@ -350,13 +349,11 @@ struct resource *amd_get_mmconfig_range(
boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
return NULL;
- /* assume all cpus from fam10h have mmconfig */
- if (boot_cpu_data.x86 < 0x10)
+ /* Assume CPUs from Fam10h have mmconfig, although not all VMs do */
+ if (boot_cpu_data.x86 < 0x10 ||
+ rdmsrl_safe(MSR_FAM10H_MMIO_CONF_BASE, &msr))
return NULL;
- address = MSR_FAM10H_MMIO_CONF_BASE;
- rdmsrl(address, msr);
-
/* mmconfig is not enabled */
if (!(msr & FAM10H_MMIO_CONF_ENABLE))
return NULL;
Patches currently in stable-queue which might be from andrew.cooper3@xxxxxxxxxx are
queue-6.1/x86-amd_nb-use-rdmsr_safe-in-amd_get_mmconfig_range.patch
