From 02d715b4a8182f4887d82df82a7b83aced647760 Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Sun, 23 Feb 2020 22:25:39 +0530 Subject: iommu/vt-d: Fix RCU list debugging warnings dmar_drhd_units is traversed using list_for_each_entry_rcu() outside of an RCU read side critical section but under the protection of dmar_global_lock. Hence add corresponding lockdep expression to silence the following false-positive warnings: [ 1.603975] ============================= [ 1.603976] WARNING: suspicious RCU usage [ 1.603977] 5.5.4-stable #17 Not tainted [ 1.603978] ----------------------------- [ 1.603980] drivers/iommu/intel-iommu.c:4769 RCU-list traversed in non-reader section!! [ 1.603869] ============================= [ 1.603870] WARNING: suspicious RCU usage [ 1.603872] 5.5.4-stable #17 Not tainted [ 1.603874] ----------------------------- [ 1.603875] drivers/iommu/dmar.c:293 RCU-list traversed in non-reader section!! Tested-by: Madhuparna Bhowmik Signed-off-by: Amol Grover Cc: stable@vger.kernel.org Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- include/linux/dmar.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/dmar.h b/include/linux/dmar.h index f64ca27dc210..712be8bc6a7c 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -69,8 +69,9 @@ struct dmar_pci_notify_info { extern struct rw_semaphore dmar_global_lock; extern struct list_head dmar_drhd_units; -#define for_each_drhd_unit(drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) +#define for_each_drhd_unit(drhd) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) #define for_each_active_drhd_unit(drhd) \ list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ @@ -81,7 +82,8 @@ extern struct list_head dmar_drhd_units; if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, 0) {} else static inline bool dmar_rcu_check(void) -- cgit v1.2.3 From f5152416528c2295f35dd9c9bd4fb27c4032413d Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Thu, 5 Mar 2020 15:15:02 -0500 Subject: iommu/vt-d: Silence RCU-list debugging warnings Similar to the commit 02d715b4a818 ("iommu/vt-d: Fix RCU list debugging warnings"), there are several other places that call list_for_each_entry_rcu() outside of an RCU read side critical section but with dmar_global_lock held. Silence those false positives as well. drivers/iommu/intel-iommu.c:4288 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x1ad/0xb97 drivers/iommu/dmar.c:366 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffff935892c8 (dmar_global_lock){+.+.}, at: intel_iommu_init+0x125/0xb97 drivers/iommu/intel-iommu.c:5057 RCU-list traversed in non-reader section!! 1 lock held by swapper/0/1: #0: ffffffffa71892c8 (dmar_global_lock){++++}, at: intel_iommu_init+0x61a/0xb13 Signed-off-by: Qian Cai Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/dmar.c | 3 ++- include/linux/dmar.h | 6 ++++-- 2 files changed, 6 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index 071bb42bbbc5..7b16c4db40b4 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -363,7 +363,8 @@ dmar_find_dmaru(struct acpi_dmar_hardware_unit *drhd) { struct dmar_drhd_unit *dmaru; - list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list) + list_for_each_entry_rcu(dmaru, &dmar_drhd_units, list, + dmar_rcu_check()) if (dmaru->segment == drhd->segment && dmaru->reg_base_addr == drhd->address) return dmaru; diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 712be8bc6a7c..d7bf029df737 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -74,11 +74,13 @@ extern struct list_head dmar_drhd_units; dmar_rcu_check()) #define for_each_active_drhd_unit(drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (drhd->ignored) {} else #define for_each_active_iommu(i, drhd) \ - list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \ + list_for_each_entry_rcu(drhd, &dmar_drhd_units, list, \ + dmar_rcu_check()) \ if (i=drhd->iommu, drhd->ignored) {} else #define for_each_iommu(i, drhd) \ -- cgit v1.2.3 From ba3b01d7a6f4ab9f8a0557044c9a7678f64ae070 Mon Sep 17 00:00:00 2001 From: Megha Dey Date: Mon, 9 Mar 2020 13:09:46 -0700 Subject: iommu/vt-d: Fix debugfs register reads Commit 6825d3ea6cde ("iommu/vt-d: Add debugfs support to show register contents") dumps the register contents for all IOMMU devices. Currently, a 64 bit read(dmar_readq) is done for all the IOMMU registers, even though some of the registers are 32 bits, which is incorrect. Use the correct read function variant (dmar_readl/dmar_readq) while reading the contents of 32/64 bit registers respectively. Signed-off-by: Megha Dey Link: https://lore.kernel.org/r/1583784587-26126-2-git-send-email-megha.dey@linux.intel.com Acked-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu-debugfs.c | 40 +++++++++++++++++++++++-------------- include/linux/intel-iommu.h | 2 ++ 2 files changed, 27 insertions(+), 15 deletions(-) (limited to 'include') diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c index c1257bef553c..0a7791934a16 100644 --- a/drivers/iommu/intel-iommu-debugfs.c +++ b/drivers/iommu/intel-iommu-debugfs.c @@ -33,38 +33,42 @@ struct iommu_regset { #define IOMMU_REGSET_ENTRY(_reg_) \ { DMAR_##_reg_##_REG, __stringify(_reg_) } -static const struct iommu_regset iommu_regs[] = { + +static const struct iommu_regset iommu_regs_32[] = { IOMMU_REGSET_ENTRY(VER), - IOMMU_REGSET_ENTRY(CAP), - IOMMU_REGSET_ENTRY(ECAP), IOMMU_REGSET_ENTRY(GCMD), IOMMU_REGSET_ENTRY(GSTS), - IOMMU_REGSET_ENTRY(RTADDR), - IOMMU_REGSET_ENTRY(CCMD), IOMMU_REGSET_ENTRY(FSTS), IOMMU_REGSET_ENTRY(FECTL), IOMMU_REGSET_ENTRY(FEDATA), IOMMU_REGSET_ENTRY(FEADDR), IOMMU_REGSET_ENTRY(FEUADDR), - IOMMU_REGSET_ENTRY(AFLOG), IOMMU_REGSET_ENTRY(PMEN), IOMMU_REGSET_ENTRY(PLMBASE), IOMMU_REGSET_ENTRY(PLMLIMIT), + IOMMU_REGSET_ENTRY(ICS), + IOMMU_REGSET_ENTRY(PRS), + IOMMU_REGSET_ENTRY(PECTL), + IOMMU_REGSET_ENTRY(PEDATA), + IOMMU_REGSET_ENTRY(PEADDR), + IOMMU_REGSET_ENTRY(PEUADDR), +}; + +static const struct iommu_regset iommu_regs_64[] = { + IOMMU_REGSET_ENTRY(CAP), + IOMMU_REGSET_ENTRY(ECAP), + IOMMU_REGSET_ENTRY(RTADDR), + IOMMU_REGSET_ENTRY(CCMD), + IOMMU_REGSET_ENTRY(AFLOG), IOMMU_REGSET_ENTRY(PHMBASE), IOMMU_REGSET_ENTRY(PHMLIMIT), IOMMU_REGSET_ENTRY(IQH), IOMMU_REGSET_ENTRY(IQT), IOMMU_REGSET_ENTRY(IQA), - IOMMU_REGSET_ENTRY(ICS), IOMMU_REGSET_ENTRY(IRTA), IOMMU_REGSET_ENTRY(PQH), IOMMU_REGSET_ENTRY(PQT), IOMMU_REGSET_ENTRY(PQA), - IOMMU_REGSET_ENTRY(PRS), - IOMMU_REGSET_ENTRY(PECTL), - IOMMU_REGSET_ENTRY(PEDATA), - IOMMU_REGSET_ENTRY(PEADDR), - IOMMU_REGSET_ENTRY(PEUADDR), IOMMU_REGSET_ENTRY(MTRRCAP), IOMMU_REGSET_ENTRY(MTRRDEF), IOMMU_REGSET_ENTRY(MTRR_FIX64K_00000), @@ -127,10 +131,16 @@ static int iommu_regset_show(struct seq_file *m, void *unused) * by adding the offset to the pointer (virtual address). */ raw_spin_lock_irqsave(&iommu->register_lock, flag); - for (i = 0 ; i < ARRAY_SIZE(iommu_regs); i++) { - value = dmar_readq(iommu->reg + iommu_regs[i].offset); + for (i = 0 ; i < ARRAY_SIZE(iommu_regs_32); i++) { + value = dmar_readl(iommu->reg + iommu_regs_32[i].offset); + seq_printf(m, "%-16s\t0x%02x\t\t0x%016llx\n", + iommu_regs_32[i].regs, iommu_regs_32[i].offset, + value); + } + for (i = 0 ; i < ARRAY_SIZE(iommu_regs_64); i++) { + value = dmar_readq(iommu->reg + iommu_regs_64[i].offset); seq_printf(m, "%-16s\t0x%02x\t\t0x%016llx\n", - iommu_regs[i].regs, iommu_regs[i].offset, + iommu_regs_64[i].regs, iommu_regs_64[i].offset, value); } raw_spin_unlock_irqrestore(&iommu->register_lock, flag); diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index 4a16b39ae353..980234ae0312 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -123,6 +123,8 @@ #define dmar_readq(a) readq(a) #define dmar_writeq(a,v) writeq(v,a) +#define dmar_readl(a) readl(a) +#define dmar_writel(a, v) writel(v, a) #define DMAR_VER_MAJOR(v) (((v) & 0xf0) >> 4) #define DMAR_VER_MINOR(v) ((v) & 0x0f) -- cgit v1.2.3