From 70479c012b67b89e219c40eddc5dc338b7c447a3 Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Sat, 15 Sep 2018 14:58:23 -0700 Subject: [PATCH] x86/intel_rdt: Fix unchecked MSR access 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: unchecked MSR access error: WRMSR to 0xd51 (tried to write 0x0000 000000000064) at rIP: 0xffffffffae059994 (native_write_msr+0x4/0x20) Call Trace: mba_wrmsr+0x41/0x80 update_domains+0x125/0x130 rdtgroup_mkdir+0x270/0x500 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 Signed-off-by: Fenghua Yu Signed-off-by: Thomas Gleixner Cc: "H Peter Anvin" Cc: "Tony Luck" Cc: "Xiaochen Shen" Cc: "Chen Yu" Link: https://lkml.kernel.org/r/1537048707-76280-6-git-send-email-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"); -- 2.30.2