4.17-stable review patch. If anyone has any objections, please let me know.
------------------ From: M. Vefa Bicakci <[email protected]> commit 405c018a25fe464dc68057bbc8014a58f2bd4422 upstream. Commit d94a155c59c9 ("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 get_cpu_address_sizes. 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: enlighten_pv.c::xen_start_kernel mmu_pv.c::xen_reserve_special_pages page.h::__pa physaddr.c::__phys_addr physaddr.h::phys_addr_valid 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: M. Vefa Bicakci <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Juergen Gross <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] # for v4.17 and up Fixes: d94a155c59c9 ("x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption") Signed-off-by: Boris Ostrovsky <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/cpu/common.c | 2 +- arch/x86/kernel/cpu/cpu.h | 1 + arch/x86/xen/enlighten_pv.c | 3 +++ 3 files changed, 5 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -883,7 +883,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c) apply_forced_caps(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; --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -46,6 +46,7 @@ extern const struct cpu_dev *const __x86 *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 int detect_extended_topology_early(struct cpuinfo_x86 *c); extern int detect_ht_early(struct cpuinfo_x86 *c); --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1258,6 +1258,9 @@ asmlinkage __visible void __init xen_sta get_cpu_cap(&boot_cpu_data); x86_configure_nx(); + /* Determine virtual and physical address sizes */ + get_cpu_address_sizes(&boot_cpu_data); + /* Let's presume PV guests always boot on vCPU with id 0. */ per_cpu(xen_vcpu_id, 0) = 0; _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
