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Commit 57a9a117 authored by Eric Auger's avatar Eric Auger Committed by Christoffer Dall
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KVM: arm64: vgic-its: Device table save/restore 



This patch saves the device table entries into guest RAM.
Both flat table and 2 stage tables are supported. DeviceId
indexing is used.

For each device listed in the device table, we also save
the translation table using the vgic_its_save/restore_itt
routines. Those functions will be implemented in a subsequent
patch.

On restore, devices are re-allocated and their itt are
re-built.

Signed-off-by: default avatarEric Auger <eric.auger@redhat.com>
Reviewed-by: default avatarChristoffer Dall <cdall@linaro.org>
parent dceff702

virt/kvm/arm/vgic/vgic-its.c

+189 −5
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/interrupt.h>

#include <linux/list.h>

#include <linux/uaccess.h>

#include <linux/list_sort.h>



#include <linux/irqchip/arm-gic-v3.h>
@@ -1735,7 +1736,8 @@ int vgic_its_attr_regs_access(struct kvm_device *dev, 
	return ret;

}



u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev)

static u32 compute_next_devid_offset(struct list_head *h,

				     struct its_device *dev)

{

	struct its_device *next;

	u32 next_offset;
@@ -1789,7 +1791,7 @@ typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry, 
 * Return: < 0 on error, 0 if last element was identified, 1 otherwise

 * (the last element may not be found on second level tables)

 */

int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,

static int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,

			  int start_id, entry_fn_t fn, void *opaque)

{

	void *entry = kzalloc(esz, GFP_KERNEL);
@@ -1825,13 +1827,171 @@ int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz, 
	return ret;

}



static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)

{

	return -ENXIO;

}



static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)

{

	return -ENXIO;

}



/**

 * vgic_its_save_dte - Save a device table entry at a given GPA

 *

 * @its: ITS handle

 * @dev: ITS device

 * @ptr: GPA

 */

static int vgic_its_save_dte(struct vgic_its *its, struct its_device *dev,

			     gpa_t ptr, int dte_esz)

{

	struct kvm *kvm = its->dev->kvm;

	u64 val, itt_addr_field;

	u32 next_offset;



	itt_addr_field = dev->itt_addr >> 8;

	next_offset = compute_next_devid_offset(&its->device_list, dev);

	val = (1ULL << KVM_ITS_DTE_VALID_SHIFT |

	       ((u64)next_offset << KVM_ITS_DTE_NEXT_SHIFT) |

	       (itt_addr_field << KVM_ITS_DTE_ITTADDR_SHIFT) |

		(dev->num_eventid_bits - 1));

	val = cpu_to_le64(val);

	return kvm_write_guest(kvm, ptr, &val, dte_esz);

}



/**

 * vgic_its_restore_dte - restore a device table entry

 *

 * @its: its handle

 * @id: device id the DTE corresponds to

 * @ptr: kernel VA where the 8 byte DTE is located

 * @opaque: unused

 *

 * Return: < 0 on error, 0 if the dte is the last one, id offset to the

 * next dte otherwise

 */

static int vgic_its_restore_dte(struct vgic_its *its, u32 id,

				void *ptr, void *opaque)

{

	struct its_device *dev;

	gpa_t itt_addr;

	u8 num_eventid_bits;

	u64 entry = *(u64 *)ptr;

	bool valid;

	u32 offset;

	int ret;



	entry = le64_to_cpu(entry);



	valid = entry >> KVM_ITS_DTE_VALID_SHIFT;

	num_eventid_bits = (entry & KVM_ITS_DTE_SIZE_MASK) + 1;

	itt_addr = ((entry & KVM_ITS_DTE_ITTADDR_MASK)

			>> KVM_ITS_DTE_ITTADDR_SHIFT) << 8;



	if (!valid)

		return 1;



	/* dte entry is valid */

	offset = (entry & KVM_ITS_DTE_NEXT_MASK) >> KVM_ITS_DTE_NEXT_SHIFT;



	dev = vgic_its_alloc_device(its, id, itt_addr, num_eventid_bits);

	if (IS_ERR(dev))

		return PTR_ERR(dev);



	ret = vgic_its_restore_itt(its, dev);

	if (ret)

		return ret;



	return offset;

}



static int vgic_its_device_cmp(void *priv, struct list_head *a,

			       struct list_head *b)

{

	struct its_device *deva = container_of(a, struct its_device, dev_list);

	struct its_device *devb = container_of(b, struct its_device, dev_list);



	if (deva->device_id < devb->device_id)

		return -1;

	else

		return 1;

}



/**

 * vgic_its_save_device_tables - Save the device table and all ITT

 * into guest RAM

 *

 * L1/L2 handling is hidden by vgic_its_check_id() helper which directly

 * returns the GPA of the device entry

 */

static int vgic_its_save_device_tables(struct vgic_its *its)

{

	return -ENXIO;

	const struct vgic_its_abi *abi = vgic_its_get_abi(its);

	struct its_device *dev;

	int dte_esz = abi->dte_esz;

	u64 baser;



	baser = its->baser_device_table;



	list_sort(NULL, &its->device_list, vgic_its_device_cmp);



	list_for_each_entry(dev, &its->device_list, dev_list) {

		int ret;

		gpa_t eaddr;



		if (!vgic_its_check_id(its, baser,

				       dev->device_id, &eaddr))

			return -EINVAL;



		ret = vgic_its_save_itt(its, dev);

		if (ret)

			return ret;



		ret = vgic_its_save_dte(its, dev, eaddr, dte_esz);

		if (ret)

			return ret;

	}

	return 0;

}



/**

 * handle_l1_dte - callback used for L1 device table entries (2 stage case)

 *

 * @its: its handle

 * @id: index of the entry in the L1 table

 * @addr: kernel VA

 * @opaque: unused

 *

 * L1 table entries are scanned by steps of 1 entry

 * Return < 0 if error, 0 if last dte was found when scanning the L2

 * table, +1 otherwise (meaning next L1 entry must be scanned)

 */

static int handle_l1_dte(struct vgic_its *its, u32 id, void *addr,

			 void *opaque)

{

	const struct vgic_its_abi *abi = vgic_its_get_abi(its);

	int l2_start_id = id * (SZ_64K / abi->dte_esz);

	u64 entry = *(u64 *)addr;

	int dte_esz = abi->dte_esz;

	gpa_t gpa;

	int ret;



	entry = le64_to_cpu(entry);



	if (!(entry & KVM_ITS_L1E_VALID_MASK))

		return 1;



	gpa = entry & KVM_ITS_L1E_ADDR_MASK;



	ret = scan_its_table(its, gpa, SZ_64K, dte_esz,

			     l2_start_id, vgic_its_restore_dte, NULL);



	if (ret <= 0)

		return ret;



	return 1;

}



/**
@@ -1840,7 +2000,31 @@ static int vgic_its_save_device_tables(struct vgic_its *its) 
 */

static int vgic_its_restore_device_tables(struct vgic_its *its)

{

	return -ENXIO;

	const struct vgic_its_abi *abi = vgic_its_get_abi(its);

	u64 baser = its->baser_device_table;

	int l1_esz, ret;

	int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;

	gpa_t l1_gpa;



	if (!(baser & GITS_BASER_VALID))

		return 0;



	l1_gpa = BASER_ADDRESS(baser);



	if (baser & GITS_BASER_INDIRECT) {

		l1_esz = GITS_LVL1_ENTRY_SIZE;

		ret = scan_its_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,

				     handle_l1_dte, NULL);

	} else {

		l1_esz = abi->dte_esz;

		ret = scan_its_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,

				     vgic_its_restore_dte, NULL);

	}



	if (ret > 0)

		ret = -EINVAL;



	return ret;

}



static int vgic_its_save_cte(struct vgic_its *its,

virt/kvm/arm/vgic/vgic.h

+10 −0
Original line number Diff line number Diff line
@@ -81,6 +81,16 @@ 
#define KVM_ITS_CTE_VALID_MASK		BIT_ULL(63)

#define KVM_ITS_CTE_RDBASE_SHIFT	16

#define KVM_ITS_CTE_ICID_MASK		GENMASK_ULL(15, 0)

#define KVM_ITS_DTE_VALID_SHIFT		63

#define KVM_ITS_DTE_VALID_MASK		BIT_ULL(63)

#define KVM_ITS_DTE_NEXT_SHIFT		49

#define KVM_ITS_DTE_NEXT_MASK		GENMASK_ULL(62, 49)

#define KVM_ITS_DTE_ITTADDR_SHIFT	5

#define KVM_ITS_DTE_ITTADDR_MASK	GENMASK_ULL(48, 5)

#define KVM_ITS_DTE_SIZE_MASK		GENMASK_ULL(4, 0)

#define KVM_ITS_L1E_VALID_MASK		BIT_ULL(63)

/* we only support 64 kB translation table page size */

#define KVM_ITS_L1E_ADDR_MASK		GENMASK_ULL(51, 16)



static inline bool irq_is_pending(struct vgic_irq *irq)

{