diff options
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 565464e3f9a5..174e7b6eba34 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1171,6 +1171,20 @@ EXPORT_SYMBOL_GPL(__kvmhv_vcpu_entry_p9) mr r4, r3 b fast_guest_entry_c guest_exit_short_path: + /* + * Malicious or buggy radix guests may have inserted SLB entries + * (only 0..3 because radix always runs with UPRT=1), so these must + * be cleared here to avoid side-channels. slbmte is used rather + * than slbia, as it won't clear cached translations. + */ + li r0,0 + slbmte r0,r0 + li r4,1 + slbmte r0,r4 + li r4,2 + slbmte r0,r4 + li r4,3 + slbmte r0,r4 li r0, KVM_GUEST_MODE_NONE stb r0, HSTATE_IN_GUEST(r13) @@ -1483,7 +1497,7 @@ guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */ lbz r0, KVM_RADIX(r5) li r5, 0 cmpwi r0, 0 - bne 3f /* for radix, save 0 entries */ + bne 0f /* for radix, save 0 entries */ lwz r0,VCPU_SLB_NR(r9) /* number of entries in SLB */ mtctr r0 li r6,0 @@ -1504,12 +1518,9 @@ guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */ slbmte r0,r0 slbia ptesync -3: stw r5,VCPU_SLB_MAX(r9) + stw r5,VCPU_SLB_MAX(r9) /* load host SLB entries */ -BEGIN_MMU_FTR_SECTION - b 0f -END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) ld r8,PACA_SLBSHADOWPTR(r13) .rept SLB_NUM_BOLTED @@ -1522,7 +1533,17 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) slbmte r6,r5 1: addi r8,r8,16 .endr -0: + b guest_bypass + +0: /* Sanitise radix guest SLB, see guest_exit_short_path comment. */ + li r0,0 + slbmte r0,r0 + li r4,1 + slbmte r0,r4 + li r4,2 + slbmte r0,r4 + li r4,3 + slbmte r0,r4 guest_bypass: stw r12, STACK_SLOT_TRAP(r1) @@ -3325,12 +3346,14 @@ BEGIN_FTR_SECTION mtspr SPRN_DAWRX1, r0 END_FTR_SECTION_IFSET(CPU_FTR_DAWR1) + /* Clear hash and radix guest SLB, see guest_exit_short_path comment. */ + slbmte r0, r0 + slbia + BEGIN_MMU_FTR_SECTION b 4f END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) - slbmte r0, r0 - slbia ptesync ld r8, PACA_SLBSHADOWPTR(r13) .rept SLB_NUM_BOLTED |