From: Lu Baolu <baolu.lu@linux.intel.com>
To: Fenghua Yu <fenghua.yu@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
H Peter Anvin <hpa@zytor.com>,
David Woodhouse <dwmw2@infradead.org>,
Frederic Barrat <fbarrat@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Joerg Roedel <joro@8bytes.org>,
Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>, Ashok Raj <ashok.raj@intel.com>,
Jacob Jun Pan <jacob.jun.pan@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>,
Sohil Mehta <sohil.mehta@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: baolu.lu@linux.intel.com,
linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
iommu@lists.linux-foundation.org,
amd-gfx <amd-gfx@lists.freedesktop.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 11/12] x86/mmu: Allocate/free PASID
Date: Mon, 15 Jun 2020 10:13:42 +0800 [thread overview]
Message-ID: <4d759c15-d539-cd1a-569d-eefa5fb6f039@linux.intel.com> (raw)
In-Reply-To: <1592008893-9388-12-git-send-email-fenghua.yu@intel.com>
Hi Fenghua,
On 6/13/20 8:41 AM, Fenghua Yu wrote:
> A PASID is allocated for an "mm" the first time any thread attaches
> to an SVM capable device. Later device attachments (whether to the same
> device or another SVM device) will re-use the same PASID.
>
> The PASID is freed when the process exits (so no need to keep
> reference counts on how many SVM devices are sharing the PASID).
>
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> Reviewed-by: Tony Luck <tony.luck@intel.com>
> ---
> v2:
> - Define a helper free_bind() to simplify error exit code in bind_mm()
> (Thomas)
> - Fix a ret error code in bind_mm() (Thomas)
> - Change pasid's type from "int" to "unsigned int" to have consistent
> pasid type in iommu (Thomas)
> - Simplify alloc_pasid() a bit.
>
> arch/x86/include/asm/iommu.h | 2 +
> arch/x86/include/asm/mmu_context.h | 14 ++++
> drivers/iommu/intel/svm.c | 101 +++++++++++++++++++++++++----
> 3 files changed, 105 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
> index bf1ed2ddc74b..ed41259fe7ac 100644
> --- a/arch/x86/include/asm/iommu.h
> +++ b/arch/x86/include/asm/iommu.h
> @@ -26,4 +26,6 @@ arch_rmrr_sanity_check(struct acpi_dmar_reserved_memory *rmrr)
> return -EINVAL;
> }
>
> +void __free_pasid(struct mm_struct *mm);
> +
> #endif /* _ASM_X86_IOMMU_H */
> diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
> index 47562147e70b..f8c91ce8c451 100644
> --- a/arch/x86/include/asm/mmu_context.h
> +++ b/arch/x86/include/asm/mmu_context.h
> @@ -13,6 +13,7 @@
> #include <asm/tlbflush.h>
> #include <asm/paravirt.h>
> #include <asm/debugreg.h>
> +#include <asm/iommu.h>
>
> extern atomic64_t last_mm_ctx_id;
>
> @@ -117,9 +118,22 @@ static inline int init_new_context(struct task_struct *tsk,
> init_new_context_ldt(mm);
> return 0;
> }
> +
> +static inline void free_pasid(struct mm_struct *mm)
> +{
> + if (!IS_ENABLED(CONFIG_INTEL_IOMMU_SVM))
> + return;
> +
> + if (!cpu_feature_enabled(X86_FEATURE_ENQCMD))
> + return;
> +
> + __free_pasid(mm);
> +}
> +
> static inline void destroy_context(struct mm_struct *mm)
> {
> destroy_context_ldt(mm);
> + free_pasid(mm);
> }
>
> extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
> index 4e775e12ae52..27dc866b8461 100644
> --- a/drivers/iommu/intel/svm.c
> +++ b/drivers/iommu/intel/svm.c
> @@ -425,6 +425,53 @@ int intel_svm_unbind_gpasid(struct device *dev, unsigned int pasid)
> return ret;
> }
>
> +static void free_bind(struct intel_svm *svm, struct intel_svm_dev *sdev,
> + bool new_pasid)
> +{
> + if (new_pasid)
> + ioasid_free(svm->pasid);
> + kfree(svm);
> + kfree(sdev);
> +}
> +
> +/*
> + * If this mm already has a PASID, use it. Otherwise allocate a new one.
> + * Let the caller know if a new PASID is allocated via 'new_pasid'.
> + */
> +static int alloc_pasid(struct intel_svm *svm, struct mm_struct *mm,
> + unsigned int pasid_max, bool *new_pasid,
> + unsigned int flags)
> +{
> + unsigned int pasid;
> +
> + *new_pasid = false;
> +
> + /*
> + * Reuse the PASID if the mm already has a PASID and not a private
> + * PASID is requested.
> + */
> + if (mm && mm->pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
> + /*
> + * Once a PASID is allocated for this mm, the PASID
> + * stays with the mm until the mm is dropped. Reuse
> + * the PASID which has been already allocated for the
> + * mm instead of allocating a new one.
> + */
> + ioasid_set_data(mm->pasid, svm);
How about adding some sanity checks here? For example,
void *p = ioasid_find(NULL, mm->pasid, NULL);
if (!p)
ioasid_set_data(mm->pasid, svm);
else if (IS_ERR(p) || p != svm)
return INVALID_IOSASID;
Best regards,
baolu
next prev parent reply other threads:[~2020-06-15 2:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-13 0:41 [PATCH v2 00/12] x86: tag application address space for devices Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 01/12] iommu: Change type of pasid to unsigned int Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 02/12] ocxl: " Fenghua Yu
2020-06-18 8:05 ` Frederic Barrat
2020-06-18 15:37 ` Fenghua Yu
2020-06-18 16:56 ` Frederic Barrat
2020-06-13 0:41 ` [PATCH v2 03/12] iommu/vt-d: Change flags type to unsigned int in binding mm Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 04/12] docs: x86: Add documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2020-06-13 12:17 ` Lu Baolu
2020-06-15 23:16 ` Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 05/12] x86/cpufeatures: Enumerate ENQCMD and ENQCMDS instructions Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 06/12] x86/fpu/xstate: Add supervisor PASID state for ENQCMD feature Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 07/12] x86/msr-index: Define IA32_PASID MSR Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 08/12] mm: Define pasid in mm Fenghua Yu
2020-06-16 8:28 ` Jean-Philippe Brucker
2020-06-16 15:11 ` Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 09/12] fork: Clear PASID for new mm Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 10/12] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2020-06-13 0:41 ` [PATCH v2 11/12] x86/mmu: Allocate/free PASID Fenghua Yu
2020-06-13 13:07 ` Lu Baolu
2020-06-15 2:13 ` Lu Baolu [this message]
2020-06-13 0:41 ` [PATCH v2 12/12] x86/traps: Fix up invalid PASID Fenghua Yu
2020-06-15 7:53 ` Peter Zijlstra
2020-06-15 7:56 ` Peter Zijlstra
2020-06-15 15:48 ` Fenghua Yu
2020-06-15 16:03 ` Peter Zijlstra
2020-06-15 17:11 ` Luck, Tony
2020-06-15 18:12 ` Fenghua Yu
2020-06-15 18:31 ` Peter Zijlstra
2020-06-15 18:55 ` Fenghua Yu
2020-06-15 19:09 ` Peter Zijlstra
2020-06-15 20:17 ` Fenghua Yu
2020-06-15 20:51 ` Andy Lutomirski
2020-06-15 20:56 ` Luck, Tony
2020-06-15 21:18 ` Andy Lutomirski
2020-06-15 21:24 ` Luck, Tony
2020-06-15 21:53 ` Peter Zijlstra
2020-06-16 23:23 ` Fenghua Yu
2020-06-17 8:31 ` Peter Zijlstra
2020-06-15 18:19 ` Raj, Ashok
2020-06-15 18:32 ` Peter Zijlstra
2020-06-15 7:52 ` [PATCH v2 00/12] x86: tag application address space for devices Peter Zijlstra
2020-06-15 14:53 ` Fenghua Yu
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