From 7faa6eec6991715d6c1d85c192738dcac405ab89 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 7 Oct 2016 23:58:53 +0100 Subject: [PATCH] KVM: MIPS/T&E: Activate GVA page tables in guest context MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Activate the GVA page tables when in guest context. This will allow the normal Linux TLB refill handler to fill from it when guest memory is read, as well as preventing accidental reading from user memory. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/include/asm/mmu_context.h | 4 +++- arch/mips/kvm/entry.c | 16 +++++++++++++++- arch/mips/kvm/trap_emul.c | 10 ++++++---- 3 files changed, 24 insertions(+), 6 deletions(-) diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h index ddd57ad..16eb852 100644 --- a/arch/mips/include/asm/mmu_context.h +++ b/arch/mips/include/asm/mmu_context.h @@ -29,9 +29,11 @@ do { \ } \ } while (0) +extern void tlbmiss_handler_setup_pgd(unsigned long); + +/* Note: This is also implemented with uasm in arch/mips/kvm/entry.c */ #define TLBMISS_HANDLER_SETUP_PGD(pgd) \ do { \ - extern void tlbmiss_handler_setup_pgd(unsigned long); \ tlbmiss_handler_setup_pgd((unsigned long)(pgd)); \ htw_set_pwbase((unsigned long)pgd); \ } while (0) diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c index f818887..f683d12 100644 --- a/arch/mips/kvm/entry.c +++ b/arch/mips/kvm/entry.c @@ -13,6 +13,7 @@ #include #include +#include #include #include #include @@ -316,7 +317,20 @@ static void *kvm_mips_build_enter_guest(void *addr) #else uasm_i_andi(&p, K0, K0, MIPS_ENTRYHI_ASID); #endif - uasm_i_mtc0(&p, K0, C0_ENTRYHI); + + /* + * Set up KVM T&E GVA pgd. + * This does roughly the same as TLBMISS_HANDLER_SETUP_PGD(): + * - call tlbmiss_handler_setup_pgd(mm->pgd) + * - but skips write into CP0_PWBase for now + */ + UASM_i_LW(&p, A0, (int)offsetof(struct mm_struct, pgd) - + (int)offsetof(struct mm_struct, context.asid), T1); + + UASM_i_LA(&p, T9, (unsigned long)tlbmiss_handler_setup_pgd); + uasm_i_jalr(&p, RA, T9); + uasm_i_mtc0(&p, K0, C0_ENTRYHI); + uasm_i_ehb(&p); /* Disable RDHWR access */ diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c index 183150a..f39d427 100644 --- a/arch/mips/kvm/trap_emul.c +++ b/arch/mips/kvm/trap_emul.c @@ -704,6 +704,7 @@ static int kvm_trap_emul_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm; struct mm_struct *user_mm = &vcpu->arch.guest_user_mm; + struct mm_struct *mm; /* Allocate new kernel and user ASIDs if needed */ @@ -733,10 +734,9 @@ static int kvm_trap_emul_vcpu_load(struct kvm_vcpu *vcpu, int cpu) * on the mode of the Guest (Kernel/User) */ if (current->flags & PF_VCPU) { - if (KVM_GUEST_KERNEL_MODE(vcpu)) - write_c0_entryhi(cpu_asid(cpu, kern_mm)); - else - write_c0_entryhi(cpu_asid(cpu, user_mm)); + mm = KVM_GUEST_KERNEL_MODE(vcpu) ? kern_mm : user_mm; + write_c0_entryhi(cpu_asid(cpu, mm)); + TLBMISS_HANDLER_SETUP_PGD(mm->pgd); kvm_mips_suspend_mm(cpu); ehb(); } @@ -757,6 +757,7 @@ static int kvm_trap_emul_vcpu_put(struct kvm_vcpu *vcpu, int cpu) get_new_mmu_context(current->mm, cpu); } write_c0_entryhi(cpu_asid(cpu, current->mm)); + TLBMISS_HANDLER_SETUP_PGD(current->mm->pgd); kvm_mips_resume_mm(cpu); ehb(); } @@ -821,6 +822,7 @@ static int kvm_trap_emul_vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu) asid_version_mask(cpu))) get_new_mmu_context(current->mm, cpu); write_c0_entryhi(cpu_asid(cpu, current->mm)); + TLBMISS_HANDLER_SETUP_PGD(current->mm->pgd); kvm_mips_resume_mm(cpu); htw_start(); -- 2.7.4