Messages in this thread Patch in this message | | | From | Fenghua Yu <> | Subject | [PATCH 5/9] x86/intel_rdt: Fix unchecked MSR access | Date | Fri, 14 Sep 2018 13:32:05 -0700 |
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From: Reinette Chatre <reinette.chatre@intel.com>
When a new resource group is created, it is initialized with sane defaults that currently assume the resource being initialized is a CAT resource. This code path is also followed by a MBA resource that is not allocated the same as a CAT resource and as a result we encounter the following unchecked MSR access error:
[ 6944.864724] unchecked MSR access error: WRMSR to 0xd51 (tried to write 0x0000 000000000064) at rIP: 0xffffffffae059994 (native_write_msr+0x4/0x20) [ 6944.877967] Call Trace: [ 6944.880472] mba_wrmsr+0x41/0x80 [ 6944.883762] update_domains+0x125/0x130 [ 6944.887667] rdtgroup_mkdir+0x270/0x500 [ 6944.891572] kernfs_iop_mkdir+0x5d/0x80 [ 6944.895475] vfs_mkdir+0x101/0x1b0 [ 6944.898934] do_mkdirat+0x7b/0xf0 [ 6944.902308] do_syscall_64+0x5b/0x180 [ 6944.906036] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 6944.911171] RIP: 0033:0x7f5a452b5377 [ 6944.914803] Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 21 9b 2c 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d f9 9a 2c 00 f7 d8 64 89 01 48 [ 6944.933942] RSP: 002b:00007ffe18172f78 EFLAGS: 00000246 ORIG_RAX: 00000000000 00053 [ 6944.941628] RAX: ffffffffffffffda RBX: 00007ffe18174cff RCX: 00007f5a452b5377 [ 6944.948929] RDX: 0000000000000001 RSI: 00000000000001ff RDI: 00007ffe18174cff [ 6944.956168] RBP: 00007ffe18174cff R08: 00000000000001ff R09: 000056126dad8d30 [ 6944.963407] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000001ff [ 6944.970651] R13: 00007ffe181730f0 R14: 0000000000000000 R15: 00007ffe18173140
Fix the above by ensuring the initial allocation is only attempted on a CAT resource.
Fixes: 95f0b77ef ("x86/intel_rdt: Initialize new resource group with sane defaults") Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> --- arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index ea91750ba27f..74821bc457c0 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -2349,6 +2349,12 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp) u32 *ctrl; for_each_alloc_enabled_rdt_resource(r) { + /* + * Only initialize default allocations for CBM cache + * resources + */ + if (r->rid == RDT_RESOURCE_MBA) + continue; list_for_each_entry(d, &r->domains, list) { d->have_new_ctrl = false; d->new_ctrl = r->cache.shareable_bits; @@ -2386,6 +2392,12 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp) } for_each_alloc_enabled_rdt_resource(r) { + /* + * Only initialize default allocations for CBM cache + * resources + */ + if (r->rid == RDT_RESOURCE_MBA) + continue; ret = update_domains(r, rdtgrp->closid); if (ret < 0) { rdt_last_cmd_puts("failed to initialize allocations\n"); -- 2.19.0
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