On Fri, May 17, 2013 at 02:25:11PM -0700, Sanjay Lal wrote:
> - 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 <sanjayl@xxxxxxxxxxx>
> ---
> arch/mips/kvm/kvm_tlb.c | 36 +++++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/arch/mips/kvm/kvm_tlb.c b/arch/mips/kvm/kvm_tlb.c
> index 89511a9..ab2e9b0 100644
> --- a/arch/mips/kvm/kvm_tlb.c
> +++ b/arch/mips/kvm/kvm_tlb.c
> @@ -16,7 +16,10 @@
> #include <linux/mm.h>
> #include <linux/delay.h>
> #include <linux/module.h>
> +#include <linux/bootmem.h>
Is this include still needed now when you export min_low_pfn in
mips_ksyms.c?
> #include <linux/kvm_host.h>
> +#include <linux/srcu.h>
> +
>
> #include <asm/cpu.h>
> #include <asm/bootinfo.h>
> @@ -169,21 +172,27 @@ 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 +216,10 @@ 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 +322,11 @@ 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 +404,11 @@ 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];
> --
> 1.7.11.3
--
Gleb.
