From 6d17c0d1e8a66f5508082cb0fecb8afb7e9a21e4 Mon Sep 17 00:00:00 2001 From: Sanjay Lal Date: Sat, 18 May 2013 06:54:24 -0700 Subject: [PATCH] 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: Sanjay Lal Signed-off-by: Gleb Natapov --- arch/mips/kvm/kvm_tlb.c | 35 ++++++++++++++++++++++++++--------- 1 file changed, 26 insertions(+), 9 deletions(-) diff --git a/arch/mips/kvm/kvm_tlb.c b/arch/mips/kvm/kvm_tlb.c index 89511a9258d3..87d845e9e5ab 100644 --- a/arch/mips/kvm/kvm_tlb.c +++ b/arch/mips/kvm/kvm_tlb.c @@ -17,6 +17,8 @@ #include #include #include +#include + #include #include @@ -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];