diff options
| -rw-r--r-- | arch/mips/include/asm/kvm_host.h | 10 | ||||
| -rw-r--r-- | arch/mips/kvm/commpage.c | 2 | ||||
| -rw-r--r-- | arch/mips/kvm/dyntrans.c | 4 | ||||
| -rw-r--r-- | arch/mips/kvm/tlb.c | 18 |
4 files changed, 20 insertions, 14 deletions
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 5e9da2a..6c43c78 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -74,8 +74,14 @@ -/* Special address that contains the comm page, used for reducing # of traps */ -#define KVM_GUEST_COMMPAGE_ADDR 0x0 +/* + * Special address that contains the comm page, used for reducing # of traps + * This needs to be within 32Kb of 0x0 (so the zero register can be used), but + * preferably not at 0x0 so that most kernel NULL pointer dereferences can be + * caught. + */ +#define KVM_GUEST_COMMPAGE_ADDR ((PAGE_SIZE > 0x8000) ? 0 : \ + (0x8000 - PAGE_SIZE)) #define KVM_GUEST_KERNEL_MODE(vcpu) ((kvm_read_c0_guest_status(vcpu->arch.cop0) & (ST0_EXL | ST0_ERL)) || \ ((kvm_read_c0_guest_status(vcpu->arch.cop0) & KSU_USER) == 0)) diff --git a/arch/mips/kvm/commpage.c b/arch/mips/kvm/commpage.c index 2d6e976..a36b77e 100644 --- a/arch/mips/kvm/commpage.c +++ b/arch/mips/kvm/commpage.c @@ -4,7 +4,7 @@ * for more details. * * commpage, currently used for Virtual COP0 registers. - * Mapped into the guest kernel @ 0x0. + * Mapped into the guest kernel @ KVM_GUEST_COMMPAGE_ADDR. * * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. * Authors: Sanjay Lal <sanjayl@kymasys.com> diff --git a/arch/mips/kvm/dyntrans.c b/arch/mips/kvm/dyntrans.c index a3031da..8a1833b 100644 --- a/arch/mips/kvm/dyntrans.c +++ b/arch/mips/kvm/dyntrans.c @@ -93,7 +93,7 @@ int kvm_mips_trans_mfc0(union mips_instruction inst, u32 *opc, } else { mfc0_inst.i_format.opcode = lw_op; mfc0_inst.i_format.rt = inst.c0r_format.rt; - mfc0_inst.i_format.simmediate = + mfc0_inst.i_format.simmediate = KVM_GUEST_COMMPAGE_ADDR | offsetof(struct kvm_mips_commpage, cop0.reg[rd][sel]); } @@ -111,7 +111,7 @@ int kvm_mips_trans_mtc0(union mips_instruction inst, u32 *opc, mtc0_inst.i_format.opcode = sw_op; mtc0_inst.i_format.rt = inst.c0r_format.rt; - mtc0_inst.i_format.simmediate = + mtc0_inst.i_format.simmediate = KVM_GUEST_COMMPAGE_ADDR | offsetof(struct kvm_mips_commpage, cop0.reg[rd][sel]); return kvm_mips_trans_replace(vcpu, opc, mtc0_inst); diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c index 8012e68..385fbd3 100644 --- a/arch/mips/kvm/tlb.c +++ b/arch/mips/kvm/tlb.c @@ -171,23 +171,23 @@ EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_write); int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr, struct kvm_vcpu *vcpu) { - kvm_pfn_t pfn0, pfn1; + kvm_pfn_t pfn; unsigned long flags, old_entryhi = 0, vaddr = 0; - unsigned long entrylo0 = 0, entrylo1 = 0; + unsigned long entrylo[2] = { 0, 0 }; + unsigned int pair_idx; - pfn0 = CPHYSADDR(vcpu->arch.kseg0_commpage) >> PAGE_SHIFT; - pfn1 = 0; - entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) | - (0x3 << ENTRYLO_C_SHIFT) | ENTRYLO_D | ENTRYLO_V; - entrylo1 = 0; + pfn = CPHYSADDR(vcpu->arch.kseg0_commpage) >> PAGE_SHIFT; + pair_idx = (badvaddr >> PAGE_SHIFT) & 1; + entrylo[pair_idx] = mips3_paddr_to_tlbpfn(pfn << PAGE_SHIFT) | + (0x3 << ENTRYLO_C_SHIFT) | ENTRYLO_D | ENTRYLO_V; local_irq_save(flags); old_entryhi = read_c0_entryhi(); vaddr = badvaddr & (PAGE_MASK << 1); write_c0_entryhi(vaddr | kvm_mips_get_kernel_asid(vcpu)); - write_c0_entrylo0(entrylo0); - write_c0_entrylo1(entrylo1); + write_c0_entrylo0(entrylo[0]); + write_c0_entrylo1(entrylo[1]); write_c0_index(kvm_mips_get_commpage_asid(vcpu)); mtc0_tlbw_hazard(); tlb_write_indexed(); |