KVM: PPC: PV mtmsrd L=0 and mtmsr
There is also a form of mtmsr where all bits need to be addressed. While the PPC64 Linux kernel behaves resonably well here, on PPC32 we do not have an L=1 form. It does mtmsr even for simple things like only changing EE. So we need to hook into that one as well and check for a mask of bits that we deem safe to change from within guest context. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Alexander Graf
committed by
Avi Kivity
Avi Kivity
parent
819a63dc79
commit
7810927760
@@ -63,7 +63,9 @@
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#define KVM_INST_MTSPR_DSISR 0x7c1203a6
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#define KVM_INST_MTSPR_DSISR 0x7c1203a6
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#define KVM_INST_TLBSYNC 0x7c00046c
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#define KVM_INST_TLBSYNC 0x7c00046c
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#define KVM_INST_MTMSRD_L0 0x7c000164
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#define KVM_INST_MTMSRD_L1 0x7c010164
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#define KVM_INST_MTMSRD_L1 0x7c010164
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#define KVM_INST_MTMSR 0x7c000124
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static bool kvm_patching_worked = true;
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static bool kvm_patching_worked = true;
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static char kvm_tmp[1024 * 1024];
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static char kvm_tmp[1024 * 1024];
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@@ -176,6 +178,49 @@ static void kvm_patch_ins_mtmsrd(u32 *inst, u32 rt)
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kvm_patch_ins_b(inst, distance_start);
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kvm_patch_ins_b(inst, distance_start);
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}
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}
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extern u32 kvm_emulate_mtmsr_branch_offs;
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extern u32 kvm_emulate_mtmsr_reg1_offs;
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extern u32 kvm_emulate_mtmsr_reg2_offs;
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extern u32 kvm_emulate_mtmsr_reg3_offs;
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extern u32 kvm_emulate_mtmsr_orig_ins_offs;
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extern u32 kvm_emulate_mtmsr_len;
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extern u32 kvm_emulate_mtmsr[];
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static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
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{
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u32 *p;
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int distance_start;
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int distance_end;
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ulong next_inst;
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p = kvm_alloc(kvm_emulate_mtmsr_len * 4);
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if (!p)
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return;
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/* Find out where we are and put everything there */
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distance_start = (ulong)p - (ulong)inst;
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next_inst = ((ulong)inst + 4);
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distance_end = next_inst - (ulong)&p[kvm_emulate_mtmsr_branch_offs];
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/* Make sure we only write valid b instructions */
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if (distance_start > KVM_INST_B_MAX) {
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kvm_patching_worked = false;
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return;
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}
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/* Modify the chunk to fit the invocation */
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memcpy(p, kvm_emulate_mtmsr, kvm_emulate_mtmsr_len * 4);
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p[kvm_emulate_mtmsr_branch_offs] |= distance_end & KVM_INST_B_MASK;
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p[kvm_emulate_mtmsr_reg1_offs] |= rt;
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p[kvm_emulate_mtmsr_reg2_offs] |= rt;
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p[kvm_emulate_mtmsr_reg3_offs] |= rt;
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p[kvm_emulate_mtmsr_orig_ins_offs] = *inst;
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtmsr_len * 4);
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/* Patch the invocation */
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kvm_patch_ins_b(inst, distance_start);
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}
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static void kvm_map_magic_page(void *data)
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static void kvm_map_magic_page(void *data)
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{
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{
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kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE,
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kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE,
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@@ -256,6 +301,12 @@ static void kvm_check_ins(u32 *inst)
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if (get_rt(inst_rt) < 30)
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if (get_rt(inst_rt) < 30)
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kvm_patch_ins_mtmsrd(inst, inst_rt);
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kvm_patch_ins_mtmsrd(inst, inst_rt);
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break;
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break;
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case KVM_INST_MTMSR:
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case KVM_INST_MTMSRD_L0:
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/* We use r30 and r31 during the hook */
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if (get_rt(inst_rt) < 30)
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kvm_patch_ins_mtmsr(inst, inst_rt);
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break;
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}
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}
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switch (_inst) {
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switch (_inst) {
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@@ -120,3 +120,87 @@ kvm_emulate_mtmsrd_reg_offs:
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.global kvm_emulate_mtmsrd_len
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.global kvm_emulate_mtmsrd_len
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kvm_emulate_mtmsrd_len:
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kvm_emulate_mtmsrd_len:
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.long (kvm_emulate_mtmsrd_end - kvm_emulate_mtmsrd) / 4
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.long (kvm_emulate_mtmsrd_end - kvm_emulate_mtmsrd) / 4
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#define MSR_SAFE_BITS (MSR_EE | MSR_CE | MSR_ME | MSR_RI)
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#define MSR_CRITICAL_BITS ~MSR_SAFE_BITS
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.global kvm_emulate_mtmsr
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kvm_emulate_mtmsr:
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SCRATCH_SAVE
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/* Fetch old MSR in r31 */
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LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
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/* Find the changed bits between old and new MSR */
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kvm_emulate_mtmsr_reg1:
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xor r31, r0, r31
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/* Check if we need to really do mtmsr */
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LOAD_REG_IMMEDIATE(r30, MSR_CRITICAL_BITS)
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and. r31, r31, r30
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/* No critical bits changed? Maybe we can stay in the guest. */
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beq maybe_stay_in_guest
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do_mtmsr:
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SCRATCH_RESTORE
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/* Just fire off the mtmsr if it's critical */
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kvm_emulate_mtmsr_orig_ins:
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mtmsr r0
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b kvm_emulate_mtmsr_branch
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maybe_stay_in_guest:
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/* Check if we have to fetch an interrupt */
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lwz r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
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cmpwi r31, 0
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beq+ no_mtmsr
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/* Check if we may trigger an interrupt */
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kvm_emulate_mtmsr_reg2:
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andi. r31, r0, MSR_EE
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beq no_mtmsr
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b do_mtmsr
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no_mtmsr:
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/* Put MSR into magic page because we don't call mtmsr */
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kvm_emulate_mtmsr_reg3:
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STL64(r0, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
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SCRATCH_RESTORE
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/* Go back to caller */
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kvm_emulate_mtmsr_branch:
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b .
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kvm_emulate_mtmsr_end:
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.global kvm_emulate_mtmsr_branch_offs
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kvm_emulate_mtmsr_branch_offs:
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.long (kvm_emulate_mtmsr_branch - kvm_emulate_mtmsr) / 4
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.global kvm_emulate_mtmsr_reg1_offs
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kvm_emulate_mtmsr_reg1_offs:
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.long (kvm_emulate_mtmsr_reg1 - kvm_emulate_mtmsr) / 4
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.global kvm_emulate_mtmsr_reg2_offs
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kvm_emulate_mtmsr_reg2_offs:
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.long (kvm_emulate_mtmsr_reg2 - kvm_emulate_mtmsr) / 4
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.global kvm_emulate_mtmsr_reg3_offs
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kvm_emulate_mtmsr_reg3_offs:
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.long (kvm_emulate_mtmsr_reg3 - kvm_emulate_mtmsr) / 4
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.global kvm_emulate_mtmsr_orig_ins_offs
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kvm_emulate_mtmsr_orig_ins_offs:
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.long (kvm_emulate_mtmsr_orig_ins - kvm_emulate_mtmsr) / 4
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.global kvm_emulate_mtmsr_len
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kvm_emulate_mtmsr_len:
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.long (kvm_emulate_mtmsr_end - kvm_emulate_mtmsr) / 4
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