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Subject[RFC PATCH 3/5] iommu/vt-d: Enlightened PASID allocation
Date
If Intel IOMMU runs in caching mode, a.k.a. virtual IOMMU, the
IOMMU driver should rely on the emulation software to allocate
and free PASID IDs. The Intel vt-d spec revision 3.0 defines a
register set to support this. This includes a capability register,
a virtual command register and a virtual response register. Refer
to section 10.4.42, 10.4.43, 10.4.44 for more information.

This patch adds the enlightened PASID allocation/free interfaces
via the virtual command register.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-pasid.c | 70 +++++++++++++++++++++++++++++++++++++
drivers/iommu/intel-pasid.h | 13 ++++++-
include/linux/intel-iommu.h | 2 ++
3 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index 839f83974aca..fb42f0c2493e 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -28,6 +28,76 @@ static DEFINE_SPINLOCK(pasid_lock);
u32 intel_pasid_max_id = PASID_MAX;
static DEFINE_IDR(pasid_idr);

+int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int *pasid)
+{
+ u64 res;
+ u64 cap;
+ u8 err_code;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!ecap_vcs(iommu->ecap)) {
+ pr_warn("IOMMU: %s: Hardware doesn't support virtual command\n",
+ iommu->name);
+ return -ENODEV;
+ }
+
+ cap = dmar_readq(iommu->reg + DMAR_VCCAP_REG);
+ if (!(cap & DMA_VCS_PAS)) {
+ pr_warn("IOMMU: %s: Emulation software doesn't support PASID allocation\n",
+ iommu->name);
+ return -ENODEV;
+ }
+
+ raw_spin_lock_irqsave(&iommu->register_lock, flags);
+ dmar_writeq(iommu->reg + DMAR_VCMD_REG, VCMD_CMD_ALLOC);
+ IOMMU_WAIT_OP(iommu, DMAR_VCRSP_REG, dmar_readq,
+ !(res & VCMD_VRSP_IP), res);
+ raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+
+ err_code = VCMD_VRSP_EC(res);
+ switch (err_code) {
+ case VCMD_VRSP_EC_SUCCESS:
+ *pasid = VCMD_VRSP_RESULE(res);
+ break;
+ case VCMD_VRSP_EC_UNAVAIL:
+ pr_info("IOMMU: %s: No PASID available\n", iommu->name);
+ ret = -ENOMEM;
+ break;
+ default:
+ ret = -ENODEV;
+ pr_warn("IOMMU: %s: Unkonwn error code %d\n",
+ iommu->name, err_code);
+ }
+
+ return ret;
+}
+
+void vcmd_free_pasid(struct intel_iommu *iommu, unsigned int pasid)
+{
+ u64 res;
+ u8 err_code;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&iommu->register_lock, flags);
+ dmar_writeq(iommu->reg + DMAR_VCMD_REG, (pasid << 8) | VCMD_CMD_FREE);
+ IOMMU_WAIT_OP(iommu, DMAR_VCRSP_REG, dmar_readq,
+ !(res & VCMD_VRSP_IP), res);
+ raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
+
+ err_code = VCMD_VRSP_EC(res);
+ switch (err_code) {
+ case VCMD_VRSP_EC_SUCCESS:
+ break;
+ case VCMD_VRSP_EC_INVAL:
+ pr_info("IOMMU: %s: Invalid PASID\n", iommu->name);
+ break;
+ default:
+ pr_warn("IOMMU: %s: Unkonwn error code %d\n",
+ iommu->name, err_code);
+ }
+}
+
int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp)
{
int ret, min, max;
diff --git a/drivers/iommu/intel-pasid.h b/drivers/iommu/intel-pasid.h
index 381545ff9fb7..c80787d02e2d 100644
--- a/drivers/iommu/intel-pasid.h
+++ b/drivers/iommu/intel-pasid.h
@@ -19,6 +19,16 @@
#define PASID_PDE_SHIFT 6
#define MAX_NR_PASID_BITS 20

+/* Virtual command interface for enlightened pasid management. */
+#define VCMD_CMD_ALLOC 0x1
+#define VCMD_CMD_FREE 0x2
+#define VCMD_VRSP_IP 0x1
+#define VCMD_VRSP_EC(e) (((e) >> 1) & 0x3)
+#define VCMD_VRSP_EC_SUCCESS 0
+#define VCMD_VRSP_EC_UNAVAIL 1
+#define VCMD_VRSP_EC_INVAL 1
+#define VCMD_VRSP_RESULE(e) (((e) >> 8) & 0xfffff)
+
/*
* Domain ID reserved for pasid entries programmed for first-level
* only and pass-through transfer modes.
@@ -69,5 +79,6 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
struct device *dev, int pasid);
void intel_pasid_tear_down_entry(struct intel_iommu *iommu,
struct device *dev, int pasid);
-
+int vcmd_alloc_pasid(struct intel_iommu *iommu, unsigned int *pasid);
+void vcmd_free_pasid(struct intel_iommu *iommu, unsigned int pasid);
#endif /* __INTEL_PASID_H */
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index b563a61a6c39..4605eef3686c 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -173,6 +173,7 @@
#define ecap_smpwc(e) (((e) >> 48) & 0x1)
#define ecap_flts(e) (((e) >> 47) & 0x1)
#define ecap_slts(e) (((e) >> 46) & 0x1)
+#define ecap_vcs(e) (((e) >> 45) & 0x1)
#define ecap_smts(e) (((e) >> 43) & 0x1)
#define ecap_dit(e) ((e >> 41) & 0x1)
#define ecap_pasid(e) ((e >> 40) & 0x1)
@@ -289,6 +290,7 @@

/* PRS_REG */
#define DMA_PRS_PPR ((u32)1)
+#define DMA_VCS_PAS ((u64)1)

#define IOMMU_WAIT_OP(iommu, offset, op, cond, sts) \
do { \
--
2.17.1
\
 
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