Commit 405c018a authored by M. Vefa Bicakci's avatar M. Vefa Bicakci Committed by Boris Ostrovsky
Browse files

xen/pv: Call get_cpu_address_sizes to set x86_virt/phys_bits

Commit d94a155c

 ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits
adjustment corruption") has moved the query and calculation of the
x86_virt_bits and x86_phys_bits fields of the cpuinfo_x86 struct
from the get_cpu_cap function to a new function named

One of the call sites related to Xen PV VMs was unfortunately missed
in the aforementioned commit. This prevents successful boot-up of
kernel versions 4.17 and up in Xen PV VMs if CONFIG_DEBUG_VIRTUAL
is enabled, due to the following code path:


phys_addr_valid uses boot_cpu_data.x86_phys_bits to validate physical
addresses. boot_cpu_data.x86_phys_bits is no longer populated before
the call to xen_reserve_special_pages due to the aforementioned commit
though, so the validation performed by phys_addr_valid fails, which
causes __phys_addr to trigger a BUG, preventing boot-up.
Signed-off-by: default avatarM. Vefa Bicakci <>
Reviewed-by: default avatarThomas Gleixner <>
Reviewed-by: default avatarBoris Ostrovsky <>
Cc: "Kirill A. Shutemov" <>
Cc: Andy Lutomirski <>
Cc: Ingo Molnar <>
Cc: "H. Peter Anvin" <>
Cc: Thomas Gleixner <>
Cc: Boris Ostrovsky <>
Cc: Juergen Gross <>
Cc: # for v4.17 and up
Fixes: d94a155c

 ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption")
Signed-off-by: default avatarBoris Ostrovsky <>
parent bf06bad9
......@@ -911,7 +911,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
static void get_cpu_address_sizes(struct cpuinfo_x86 *c)
void get_cpu_address_sizes(struct cpuinfo_x86 *c)
u32 eax, ebx, ecx, edx;
......@@ -46,6 +46,7 @@ extern const struct cpu_dev *const __x86_cpu_dev_start[],
*const __x86_cpu_dev_end[];
extern void get_cpu_cap(struct cpuinfo_x86 *c);
extern void get_cpu_address_sizes(struct cpuinfo_x86 *c);
extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c);
extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c);
extern u32 get_scattered_cpuid_leaf(unsigned int level,
......@@ -1259,6 +1259,9 @@ asmlinkage __visible void __init xen_start_kernel(void)
/* Determine virtual and physical address sizes */
/* Let's presume PV guests always boot on vCPU with id 0. */
per_cpu(xen_vcpu_id, 0) = 0;
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