Commit f440c8a5 authored by Jike Song's avatar Jike Song Committed by Zhenyu Wang
Browse files

drm/i915/gvt/kvmgt: read/write GPA via KVM API 



Previously to read/write a GPA, we at first try to pin the GFN it belongs
to, then translate the pinned PFN to a kernel HVA, then read/write it.
This is however not necessary. A GFN should be pinned IFF it would be
accessed by peripheral devices (DMA), not by CPU. This patch changes
the read/write method to KVM API, which will leverage userspace HVA
and copy_{from|to}_usr instead.

Signed-off-by: default avatarJike Song <jike.song@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
parent c55b1de0

drivers/gpu/drm/i915/gvt/kvmgt.c

+16 −21
Original line number Original line Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/init.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/device.h>

#include <linux/mm.h>

#include <linux/mm.h>

#include <linux/mmu_context.h>

#include <linux/types.h>

#include <linux/types.h>

#include <linux/list.h>

#include <linux/list.h>

#include <linux/rbtree.h>

#include <linux/rbtree.h>
@@ -519,33 +520,27 @@ static unsigned long kvmgt_gfn_to_pfn(unsigned long handle, unsigned long gfn) 
	return pfn;

	return pfn;

}

}





static void *kvmgt_gpa_to_hva(unsigned long handle, unsigned long gpa)

{

	unsigned long pfn;

	gfn_t gfn = gpa_to_gfn(gpa);



	pfn = kvmgt_gfn_to_pfn(handle, gfn);

	if (!pfn)

		return NULL;



	return (char *)pfn_to_kaddr(pfn) + offset_in_page(gpa);

}



static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa,

static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa,

			void *buf, unsigned long len, bool write)

			void *buf, unsigned long len, bool write)

{

{

	void *hva = NULL;

	struct kvmgt_guest_info *info;

	struct kvm *kvm;

	int ret;

	bool kthread = current->mm == NULL;





	hva = kvmgt_gpa_to_hva(handle, gpa);

	info = (struct kvmgt_guest_info *)handle;

	if (!hva)

	kvm = info->kvm;

		return -EFAULT;





	if (write)

	if (kthread)

		memcpy(hva, buf, len);

		use_mm(kvm->mm);

	else

		memcpy(buf, hva, len);





	return 0;

	ret = write ? kvm_write_guest(kvm, gpa, buf, len) :

		      kvm_read_guest(kvm, gpa, buf, len);



	if (kthread)

		unuse_mm(kvm->mm);



	return ret;

}

}





static int kvmgt_read_gpa(unsigned long handle, unsigned long gpa,

static int kvmgt_read_gpa(unsigned long handle, unsigned long gpa,

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