Hi, Thomas,
On Fri, Nov 13, 2020 at 7:13 PM Thomas Bogendoerfer
<tsbogend@xxxxxxxxxxxxxxxx> wrote:
>
> MIPS protection bits are setup during runtime so using defines like
> PAGE_SHARED ignores this runtime changes. Using vm_get_page_prot
> to get correct page protection fixes this.
Is there some visible bugs if without this fix?
Huacai
>
> Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
> ---
> arch/mips/kvm/mmu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
> index 28c366d307e7..3dabeda82458 100644
> --- a/arch/mips/kvm/mmu.c
> +++ b/arch/mips/kvm/mmu.c
> @@ -1074,6 +1074,7 @@ int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
> {
> kvm_pfn_t pfn;
> pte_t *ptep;
> + pgprot_t prot;
>
> ptep = kvm_trap_emul_pte_for_gva(vcpu, badvaddr);
> if (!ptep) {
> @@ -1083,7 +1084,8 @@ int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
>
> pfn = PFN_DOWN(virt_to_phys(vcpu->arch.kseg0_commpage));
> /* Also set valid and dirty, so refill handler doesn't have to */
> - *ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, PAGE_SHARED)));
> + prot = vm_get_page_prot(VM_READ|VM_WRITE|VM_SHARED);
> + *ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, prot)));
>
> /* Invalidate this entry in the TLB, guest kernel ASID only */
> kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
> --
> 2.16.4
>
