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Subject[PATCH v6 10/18] virt: acrn: Introduce PCI configuration space PIO accesses combiner
Date
From: Shuo Liu <shuo.a.liu@intel.com>

A User VM can access its virtual PCI configuration spaces via port IO
approach, which has two following steps:
1) writes address into port 0xCF8
2) put/get data in/from port 0xCFC

To distribute a complete PCI configuration space access one time, HSM
need to combine such two accesses together.

Combine two paired PIO I/O requests into one PCI I/O request and
continue the I/O request distribution.

Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/virt/acrn/acrn_drv.h | 2 +
drivers/virt/acrn/ioreq.c | 76 ++++++++++++++++++++++++++++++++++++
include/uapi/linux/acrn.h | 15 +++++++
3 files changed, 93 insertions(+)

diff --git a/drivers/virt/acrn/acrn_drv.h b/drivers/virt/acrn/acrn_drv.h
index 7e89e4944d0f..97a7f31cd681 100644
--- a/drivers/virt/acrn/acrn_drv.h
+++ b/drivers/virt/acrn/acrn_drv.h
@@ -154,6 +154,7 @@ extern rwlock_t acrn_vm_list_lock;
* @default_client: The default I/O request client
* @ioreq_buf: I/O request shared buffer
* @ioreq_page: The page of the I/O request shared buffer
+ * @pci_conf_addr: Address of a PCI configuration access emulation
*/
struct acrn_vm {
struct list_head list;
@@ -168,6 +169,7 @@ struct acrn_vm {
struct acrn_ioreq_client *default_client;
struct acrn_io_request_buffer *ioreq_buf;
struct page *ioreq_page;
+ u32 pci_conf_addr;
};

struct acrn_vm *acrn_vm_create(struct acrn_vm *vm,
diff --git a/drivers/virt/acrn/ioreq.c b/drivers/virt/acrn/ioreq.c
index ed22b1c4775d..b469f273e20c 100644
--- a/drivers/virt/acrn/ioreq.c
+++ b/drivers/virt/acrn/ioreq.c
@@ -220,6 +220,80 @@ int acrn_ioreq_client_wait(struct acrn_ioreq_client *client)
return 0;
}

+static bool is_cfg_addr(struct acrn_io_request *req)
+{
+ return ((req->type == ACRN_IOREQ_TYPE_PORTIO) &&
+ (req->reqs.pio_request.address == 0xcf8));
+}
+
+static bool is_cfg_data(struct acrn_io_request *req)
+{
+ return ((req->type == ACRN_IOREQ_TYPE_PORTIO) &&
+ ((req->reqs.pio_request.address >= 0xcfc) &&
+ (req->reqs.pio_request.address < (0xcfc + 4))));
+}
+
+/* The low 8-bit of supported pci_reg addr.*/
+#define PCI_LOWREG_MASK 0xFC
+/* The high 4-bit of supported pci_reg addr */
+#define PCI_HIGHREG_MASK 0xF00
+/* Max number of supported functions */
+#define PCI_FUNCMAX 7
+/* Max number of supported slots */
+#define PCI_SLOTMAX 31
+/* Max number of supported buses */
+#define PCI_BUSMAX 255
+#define CONF1_ENABLE 0x80000000UL
+/*
+ * A PCI configuration space access via PIO 0xCF8 and 0xCFC normally has two
+ * following steps:
+ * 1) writes address into 0xCF8 port
+ * 2) accesses data in/from 0xCFC
+ * This function combines such paired PCI configuration space I/O requests into
+ * one ACRN_IOREQ_TYPE_PCICFG type I/O request and continues the processing.
+ */
+static bool handle_cf8cfc(struct acrn_vm *vm,
+ struct acrn_io_request *req, u16 vcpu)
+{
+ int offset, pci_cfg_addr, pci_reg;
+ bool is_handled = false;
+
+ if (is_cfg_addr(req)) {
+ WARN_ON(req->reqs.pio_request.size != 4);
+ if (req->reqs.pio_request.direction == ACRN_IOREQ_DIR_WRITE)
+ vm->pci_conf_addr = req->reqs.pio_request.value;
+ else
+ req->reqs.pio_request.value = vm->pci_conf_addr;
+ is_handled = true;
+ } else if (is_cfg_data(req)) {
+ if (!(vm->pci_conf_addr & CONF1_ENABLE)) {
+ if (req->reqs.pio_request.direction ==
+ ACRN_IOREQ_DIR_READ)
+ req->reqs.pio_request.value = 0xffffffff;
+ is_handled = true;
+ } else {
+ offset = req->reqs.pio_request.address - 0xcfc;
+
+ req->type = ACRN_IOREQ_TYPE_PCICFG;
+ pci_cfg_addr = vm->pci_conf_addr;
+ req->reqs.pci_request.bus =
+ (pci_cfg_addr >> 16) & PCI_BUSMAX;
+ req->reqs.pci_request.dev =
+ (pci_cfg_addr >> 11) & PCI_SLOTMAX;
+ req->reqs.pci_request.func =
+ (pci_cfg_addr >> 8) & PCI_FUNCMAX;
+ pci_reg = (pci_cfg_addr & PCI_LOWREG_MASK) +
+ ((pci_cfg_addr >> 16) & PCI_HIGHREG_MASK);
+ req->reqs.pci_request.reg = pci_reg + offset;
+ }
+ }
+
+ if (is_handled)
+ ioreq_complete_request(vm, vcpu, req);
+
+ return is_handled;
+}
+
static bool in_range(struct acrn_ioreq_range *range,
struct acrn_io_request *req)
{
@@ -380,6 +454,8 @@ static int acrn_ioreq_dispatch(struct acrn_vm *vm)
ioreq_complete_request(vm, i, req);
continue;
}
+ if (handle_cf8cfc(vm, req, i))
+ continue;

spin_lock_bh(&vm->ioreq_clients_lock);
client = find_ioreq_client(vm, req);
diff --git a/include/uapi/linux/acrn.h b/include/uapi/linux/acrn.h
index 96ebc879b8d0..66c43bd1e1b3 100644
--- a/include/uapi/linux/acrn.h
+++ b/include/uapi/linux/acrn.h
@@ -21,6 +21,7 @@

#define ACRN_IOREQ_TYPE_PORTIO 0
#define ACRN_IOREQ_TYPE_MMIO 1
+#define ACRN_IOREQ_TYPE_PCICFG 2

#define ACRN_IOREQ_DIR_READ 0
#define ACRN_IOREQ_DIR_WRITE 1
@@ -41,6 +42,18 @@ struct acrn_pio_request {
__u32 value;
};

+/* Need keep same header fields with pio_request */
+struct acrn_pci_request {
+ __u32 direction;
+ __u32 reserved[3];
+ __u64 size;
+ __u32 value;
+ __u32 bus;
+ __u32 dev;
+ __u32 func;
+ __u32 reg;
+};
+
/**
* struct acrn_io_request - 256-byte ACRN I/O request
* @type: Type of this request (ACRN_IOREQ_TYPE_*).
@@ -49,6 +62,7 @@ struct acrn_pio_request {
* @reserved0: Reserved fields.
* @reqs: Union of different types of request. Byte offset: 64.
* @reqs.pio_request: PIO request data of the I/O request.
+ * @reqs.pci_request: PCI configuration space request data of the I/O request.
* @reqs.mmio_request: MMIO request data of the I/O request.
* @reqs.data: Raw data of the I/O request.
* @reserved1: Reserved fields.
@@ -108,6 +122,7 @@ struct acrn_io_request {
__u32 reserved0[14];
union {
struct acrn_pio_request pio_request;
+ struct acrn_pci_request pci_request;
struct acrn_mmio_request mmio_request;
__u64 data[8];
} reqs;
--
2.28.0
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