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Commit 6d17c0d1 authored by Sanjay Lal's avatar Sanjay Lal Committed by Gleb Natapov
Browse files

KVM/MIPS32: Wrap calls to gfn_to_pfn() with srcu_read_lock/unlock() 



- As suggested by Gleb, wrap calls to gfn_to_pfn() with srcu_read_lock/unlock().
  Memory slots should be acccessed from a SRCU read section.
- kvm_mips_map_page() now returns an error code to it's callers, instead of
  calling panic() if it cannot find a mapping for a particular gfn.

Signed-off-by: default avatarSanjay Lal <sanjayl@kymasys.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent ba86e4dd

arch/mips/kvm/kvm_tlb.c

+26 −9
Original line number Diff line number Diff line
@@ -17,6 +17,8 @@ 
#include <linux/delay.h>

#include <linux/module.h>

#include <linux/kvm_host.h>

#include <linux/srcu.h>





#include <asm/cpu.h>

#include <asm/bootinfo.h>
@@ -169,21 +171,27 @@ void kvm_mips_dump_shadow_tlbs(struct kvm_vcpu *vcpu) 
	}

}



static void kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)

static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)

{

	int srcu_idx, err = 0;

	pfn_t pfn;



	if (kvm->arch.guest_pmap[gfn] != KVM_INVALID_PAGE)

		return;

		return 0;



        srcu_idx = srcu_read_lock(&kvm->srcu);

	pfn = kvm_mips_gfn_to_pfn(kvm, gfn);



	if (kvm_mips_is_error_pfn(pfn)) {

		panic("Couldn't get pfn for gfn %#" PRIx64 "!\n", gfn);

		kvm_err("Couldn't get pfn for gfn %#" PRIx64 "!\n", gfn);

		err = -EFAULT;

		goto out;

	}



	kvm->arch.guest_pmap[gfn] = pfn;

	return;

out:

	srcu_read_unlock(&kvm->srcu, srcu_idx);

	return err;

}



/* Translate guest KSEG0 addresses to Host PA */
@@ -207,7 +215,10 @@ unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu, 
			gva);

		return KVM_INVALID_PAGE;

	}

	kvm_mips_map_page(vcpu->kvm, gfn);



	if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)

		return KVM_INVALID_ADDR;



	return (kvm->arch.guest_pmap[gfn] << PAGE_SHIFT) + offset;

}
@@ -310,8 +321,11 @@ int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr, 
	even = !(gfn & 0x1);

	vaddr = badvaddr & (PAGE_MASK << 1);



	kvm_mips_map_page(vcpu->kvm, gfn);

	kvm_mips_map_page(vcpu->kvm, gfn ^ 0x1);

	if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)

		return -1;



	if (kvm_mips_map_page(vcpu->kvm, gfn ^ 0x1) < 0)

		return -1;



	if (even) {

		pfn0 = kvm->arch.guest_pmap[gfn];
@@ -389,8 +403,11 @@ kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu, 
		pfn0 = 0;

		pfn1 = 0;

	} else {

		kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo0) >> PAGE_SHIFT);

		kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo1) >> PAGE_SHIFT);

		if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo0) >> PAGE_SHIFT) < 0)

			return -1;



		if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo1) >> PAGE_SHIFT) < 0)

			return -1;



		pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo0) >> PAGE_SHIFT];

		pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo1) >> PAGE_SHIFT];