[PATCH v1 10/22] intel_iommu: add virtual command capability support

Liu Yi L
2020-03-22T12:31:01Z

This patch adds virtual command support to Intel vIOMMU per
Intel VT-d 3.1 spec. And adds two virtual commands: allocate
pasid and free pasid.

Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Yi Sun <yi.y.sun@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
---
hw/i386/intel_iommu.c | 154 ++++++++++++++++++++++++++++++++++++++++-
hw/i386/intel_iommu_internal.h | 37 ++++++++++
hw/i386/trace-events | 1 +
include/hw/i386/intel_iommu.h | 10 ++-
4 files changed, 200 insertions(+), 2 deletions(-)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 8d9204f..0c402e4 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -2651,6 +2651,129 @@ static void vtd_handle_iectl_write(IntelIOMMUState *s)
}
}

+static int vtd_request_pasid_alloc(IntelIOMMUState *s, uint32_t *pasid)
+{
+ VTDHostIOMMUContext *vtd_dev_icx;
+ int ret = -1;
+
+ vtd_iommu_lock(s);
+ QLIST_FOREACH(vtd_dev_icx, &s->vtd_dev_icx_list, next) {
+ HostIOMMUContext *host_icx = vtd_dev_icx->host_icx;
+
+ /*
+ * We'll return the first valid result we got. It's
+ * a bit hackish in that we don't have a good global
+ * interface yet to talk to modules like vfio to deliver
+ * this allocation request, so we're leveraging this
+ * per-device iommu context to do the same thing just
+ * to make sure the allocation happens only once.
+ */
+ ret = host_iommu_ctx_pasid_alloc(host_icx, VTD_MIN_HPASID,
+ VTD_MAX_HPASID, pasid);
+ if (!ret) {
+ break;
+ }
+ }
+ vtd_iommu_unlock(s);
+
+ return ret;
+}
+
+static int vtd_request_pasid_free(IntelIOMMUState *s, uint32_t pasid)
+{
+ VTDHostIOMMUContext *vtd_dev_icx;
+ int ret = -1;
+
+ vtd_iommu_lock(s);
+ QLIST_FOREACH(vtd_dev_icx, &s->vtd_dev_icx_list, next) {
+ HostIOMMUContext *host_icx = vtd_dev_icx->host_icx;
+
+ /*
+ * Similar with pasid allocation. We'll free the pasid
+ * on the first successful free operation. It's a bit
+ * hackish in that we don't have a good global interface
+ * yet to talk to modules like vfio to deliver this pasid
+ * free request, so we're leveraging this per-device iommu
+ * context to do the same thing just to make sure the free
+ * happens only once.
+ */
+ ret = host_iommu_ctx_pasid_free(host_icx, pasid);
+ if (!ret) {
+ break;
+ }
+ }
+ vtd_iommu_unlock(s);
+
+ return ret;
+}
+
+/*
+ * If IP is not set, set it then return.
+ * If IP is already set, return.
+ */
+static void vtd_vcmd_set_ip(IntelIOMMUState *s)
+{
+ s->vcrsp = 1;
+ vtd_set_quad_raw(s, DMAR_VCRSP_REG,
+ ((uint64_t) s->vcrsp));
+}
+
+static void vtd_vcmd_clear_ip(IntelIOMMUState *s)
+{
+ s->vcrsp &= (~((uint64_t)(0x1)));
+ vtd_set_quad_raw(s, DMAR_VCRSP_REG,
+ ((uint64_t) s->vcrsp));
+}
+
+/* Handle write to Virtual Command Register */
+static int vtd_handle_vcmd_write(IntelIOMMUState *s, uint64_t val)
+{
+ uint32_t pasid;
+ int ret = -1;
+
+ trace_vtd_reg_write_vcmd(s->vcrsp, val);
+
+ if (!(s->vccap & VTD_VCCAP_PAS) ||
+ (s->vcrsp & 1)) {
+ return -1;
+ }
+
+ /*
+ * Since vCPU should be blocked when the guest VMCD
+ * write was trapped to here. Should be no other vCPUs
+ * try to access VCMD if guest software is well written.
+ * However, we still emulate the IP bit here in case of
+ * bad guest software. Also align with the spec.
+ */
+ vtd_vcmd_set_ip(s);
+
+ switch (val & VTD_VCMD_CMD_MASK) {
+ case VTD_VCMD_ALLOC_PASID:
+ ret = vtd_request_pasid_alloc(s, &pasid);
+ if (ret) {
+ s->vcrsp |= VTD_VCRSP_SC(VTD_VCMD_NO_AVAILABLE_PASID);
+ } else {
+ s->vcrsp |= VTD_VCRSP_RSLT(pasid);
+ }
+ break;
+
+ case VTD_VCMD_FREE_PASID:
+ pasid = VTD_VCMD_PASID_VALUE(val);
+ ret = vtd_request_pasid_free(s, pasid);
+ if (ret < 0) {
+ s->vcrsp |= VTD_VCRSP_SC(VTD_VCMD_FREE_INVALID_PASID);
+ }
+ break;
+
+ default:
+ s->vcrsp |= VTD_VCRSP_SC(VTD_VCMD_UNDEFINED_CMD);
+ error_report_once("Virtual Command: unsupported command!!!");
+ break;
+ }
+ vtd_vcmd_clear_ip(s);
+ return 0;
+}
+
static uint64_t vtd_mem_read(void *opaque, hwaddr addr, unsigned size)
{
IntelIOMMUState *s = opaque;
@@ -2939,6 +3062,23 @@ static void vtd_mem_write(void *opaque, hwaddr addr,
vtd_set_long(s, addr, val);
break;

+ case DMAR_VCMD_REG:
+ if (!vtd_handle_vcmd_write(s, val)) {
+ if (size == 4) {
+ vtd_set_long(s, addr, val);
+ } else {
+ vtd_set_quad(s, addr, val);
+ }
+ }
+ break;
+
+ case DMAR_VCMD_REG_HI:
+ assert(size == 4);
+ if (!vtd_handle_vcmd_write(s, val)) {
+ vtd_set_long(s, addr, val);
+ }
+ break;
+
default:
if (size == 4) {
vtd_set_long(s, addr, val);
@@ -3470,6 +3610,7 @@ static int vtd_dev_set_iommu_context(PCIBus *bus, void *opaque,
vtd_dev_icx->devfn = (uint8_t)devfn;
vtd_dev_icx->iommu_state = s;
vtd_dev_icx->host_icx = host_icx;
+ QLIST_INSERT_HEAD(&s->vtd_dev_icx_list, vtd_dev_icx, next);
}
vtd_iommu_unlock(s);

@@ -3489,7 +3630,10 @@ static void vtd_dev_unset_iommu_context(PCIBus *bus, void *opaque, int devfn)
vtd_iommu_lock(s);

vtd_dev_icx = vtd_bus->dev_icx[devfn];
- g_free(vtd_dev_icx);
+ if (vtd_dev_icx) {
+ QLIST_REMOVE(vtd_dev_icx, next);
+ g_free(vtd_dev_icx);
+ }

vtd_iommu_unlock(s);
}
@@ -3763,6 +3907,13 @@ static void vtd_init(IntelIOMMUState *s)
* Interrupt remapping registers.
*/
vtd_define_quad(s, DMAR_IRTA_REG, 0, 0xfffffffffffff80fULL, 0);
+
+ /*
+ * Virtual Command Definitions
+ */
+ vtd_define_quad(s, DMAR_VCCAP_REG, s->vccap, 0, 0);
+ vtd_define_quad(s, DMAR_VCMD_REG, 0, 0xffffffffffffffffULL, 0);
+ vtd_define_quad(s, DMAR_VCRSP_REG, 0, 0, 0);
}

/* Should not reset address_spaces when reset because devices will still use
@@ -3877,6 +4028,7 @@ static void vtd_realize(DeviceState *dev, Error **errp)
}

QLIST_INIT(&s->vtd_as_with_notifiers);
+ QLIST_INIT(&s->vtd_dev_icx_list);
qemu_mutex_init(&s->iommu_lock);
memset(s->vtd_as_by_bus_num, 0, sizeof(s->vtd_as_by_bus_num));
memory_region_init_io(&s->csrmem, OBJECT(s), &vtd_mem_ops, s,
diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
index 862033e..1d997a1 100644
--- a/hw/i386/intel_iommu_internal.h
+++ b/hw/i386/intel_iommu_internal.h
@@ -85,6 +85,12 @@
#define DMAR_MTRRCAP_REG_HI 0x104
#define DMAR_MTRRDEF_REG 0x108 /* MTRR default type */
#define DMAR_MTRRDEF_REG_HI 0x10c
+#define DMAR_VCCAP_REG 0xE00 /* Virtual Command Capability Register */
+#define DMAR_VCCAP_REG_HI 0xE04
+#define DMAR_VCMD_REG 0xE10 /* Virtual Command Register */
+#define DMAR_VCMD_REG_HI 0xE14
+#define DMAR_VCRSP_REG 0xE20 /* Virtual Command Reponse Register */
+#define DMAR_VCRSP_REG_HI 0xE24

/* IOTLB registers */
#define DMAR_IOTLB_REG_OFFSET 0xf0 /* Offset to the IOTLB registers */
@@ -312,6 +318,37 @@ typedef enum VTDFaultReason {

#define VTD_CONTEXT_CACHE_GEN_MAX 0xffffffffUL

+/* VCCAP_REG */
+#define VTD_VCCAP_PAS (1UL << 0)
+
+/*
+ * The basic idea is to let hypervisor to set a range for available
+ * PASIDs for VMs. One of the reasons is PASID #0 is reserved by
+ * RID_PASID usage. We have no idea how many reserved PASIDs in future,
+ * so here just an evaluated value. Honestly, set it as "1" is enough
+ * at current stage.
+ */
+#define VTD_MIN_HPASID 1
+#define VTD_MAX_HPASID 0xFFFFF
+
+/* Virtual Command Register */
+enum {
+ VTD_VCMD_NULL_CMD = 0,
+ VTD_VCMD_ALLOC_PASID = 1,
+ VTD_VCMD_FREE_PASID = 2,
+ VTD_VCMD_CMD_NUM,
+};
+
+#define VTD_VCMD_CMD_MASK 0xffUL
+#define VTD_VCMD_PASID_VALUE(val) (((val) >> 8) & 0xfffff)
+
+#define VTD_VCRSP_RSLT(val) ((val) << 8)
+#define VTD_VCRSP_SC(val) (((val) & 0x3) << 1)
+
+#define VTD_VCMD_UNDEFINED_CMD 1ULL
+#define VTD_VCMD_NO_AVAILABLE_PASID 2ULL
+#define VTD_VCMD_FREE_INVALID_PASID 2ULL
+
/* Interrupt Entry Cache Invalidation Descriptor: VT-d 6.5.2.7. */
struct VTDInvDescIEC {
uint32_t type:4; /* Should always be 0x4 */
diff --git a/hw/i386/trace-events b/hw/i386/trace-events
index e48bef2..71536a7 100644
--- a/hw/i386/trace-events
+++ b/hw/i386/trace-events
@@ -51,6 +51,7 @@ vtd_reg_write_gcmd(uint32_t status, uint32_t val) "status 0x%"PRIx32" value 0x%"
vtd_reg_write_fectl(uint32_t value) "value 0x%"PRIx32
vtd_reg_write_iectl(uint32_t value) "value 0x%"PRIx32
vtd_reg_ics_clear_ip(void) ""
+vtd_reg_write_vcmd(uint32_t status, uint32_t val) "status 0x%"PRIx32" value 0x%"PRIx32
vtd_dmar_translate(uint8_t bus, uint8_t slot, uint8_t func, uint64_t iova, uint64_t gpa, uint64_t mask) "dev %02x:%02x.%02x iova 0x%"PRIx64" -> gpa 0x%"PRIx64" mask 0x%"PRIx64
vtd_dmar_enable(bool en) "enable %d"
vtd_dmar_fault(uint16_t sid, int fault, uint64_t addr, bool is_write) "sid 0x%"PRIx16" fault %d addr 0x%"PRIx64" write %d"
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 9b4fc0a..da0a5f7 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -42,7 +42,7 @@
#define VTD_SID_TO_BUS(sid) (((sid) >> 8) & 0xff)
#define VTD_SID_TO_DEVFN(sid) ((sid) & 0xff)

-#define DMAR_REG_SIZE 0x230
+#define DMAR_REG_SIZE 0xF00
#define VTD_HOST_AW_39BIT 39
#define VTD_HOST_AW_48BIT 48
#define VTD_HOST_ADDRESS_WIDTH VTD_HOST_AW_39BIT
@@ -118,6 +118,7 @@ struct VTDHostIOMMUContext {
uint8_t devfn;
HostIOMMUContext *host_icx;
IntelIOMMUState *iommu_state;
+ QLIST_ENTRY(VTDHostIOMMUContext) next;
};

struct VTDBus {
@@ -269,6 +270,9 @@ struct IntelIOMMUState {
/* list of registered notifiers */
QLIST_HEAD(, VTDAddressSpace) vtd_as_with_notifiers;

+ /* list of VTDHostIOMMUContexts */
+ QLIST_HEAD(, VTDHostIOMMUContext) vtd_dev_icx_list;
+
/* interrupt remapping */
bool intr_enabled; /* Whether guest enabled IR */
dma_addr_t intr_root; /* Interrupt remapping table pointer */
@@ -279,6 +283,10 @@ struct IntelIOMMUState {
uint8_t aw_bits; /* Host/IOVA address width (in bits) */
bool dma_drain; /* Whether DMA r/w draining enabled */

+ /* Virtual Command Register */
+ uint64_t vccap; /* The value of vcmd capability reg */
+ uint64_t vcrsp; /* Current value of VCMD RSP REG */
+
/*
* Protects IOMMU states in general. Currently it protects the
* per-IOMMU IOTLB cache, and context entry cache in VTDAddressSpace.
--
2.7.4