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KVM: PPC: Add mtsrin PV code
This is the guest side of the mtsr acceleration. Using this a guest can now call mtsrin with almost no overhead as long as it ensures that it only uses it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good. Signed-off-by: Alexander Graf <agraf@suse.de>
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4 changed files with 114 additions and 0 deletions
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@ -160,6 +160,9 @@ mtmsr rX b <special mtmsr section>
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mtmsrd rX, 1 b <special mtmsrd section>
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[Book3S only]
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mtsrin rX, rY b <special mtsrin section>
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[BookE only]
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wrteei [0|1] b <special wrteei section>
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@ -478,6 +478,7 @@ int main(void)
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DEFINE(KVM_MAGIC_MSR, offsetof(struct kvm_vcpu_arch_shared, msr));
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DEFINE(KVM_MAGIC_CRITICAL, offsetof(struct kvm_vcpu_arch_shared,
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critical));
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DEFINE(KVM_MAGIC_SR, offsetof(struct kvm_vcpu_arch_shared, sr));
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#endif
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#ifdef CONFIG_44x
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@ -42,6 +42,7 @@
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#define KVM_INST_B_MAX 0x01ffffff
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#define KVM_MASK_RT 0x03e00000
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#define KVM_MASK_RB 0x0000f800
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#define KVM_INST_MFMSR 0x7c0000a6
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#define KVM_INST_MFSPR_SPRG0 0x7c1042a6
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#define KVM_INST_MFSPR_SPRG1 0x7c1142a6
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@ -69,6 +70,8 @@
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#define KVM_INST_WRTEEI_0 0x7c000146
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#define KVM_INST_WRTEEI_1 0x7c008146
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#define KVM_INST_MTSRIN 0x7c0001e4
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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 int kvm_tmp_index;
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@ -264,6 +267,51 @@ static void kvm_patch_ins_wrteei(u32 *inst)
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#endif
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#ifdef CONFIG_PPC_BOOK3S_32
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extern u32 kvm_emulate_mtsrin_branch_offs;
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extern u32 kvm_emulate_mtsrin_reg1_offs;
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extern u32 kvm_emulate_mtsrin_reg2_offs;
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extern u32 kvm_emulate_mtsrin_orig_ins_offs;
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extern u32 kvm_emulate_mtsrin_len;
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extern u32 kvm_emulate_mtsrin[];
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static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb)
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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_mtsrin_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_mtsrin_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_mtsrin, kvm_emulate_mtsrin_len * 4);
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p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK;
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p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10);
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p[kvm_emulate_mtsrin_reg2_offs] |= rt;
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p[kvm_emulate_mtsrin_orig_ins_offs] = *inst;
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flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_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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#endif
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static void kvm_map_magic_page(void *data)
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{
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u32 *features = data;
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@ -360,6 +408,18 @@ static void kvm_check_ins(u32 *inst, u32 features)
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break;
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}
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switch (inst_no_rt & ~KVM_MASK_RB) {
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#ifdef CONFIG_PPC_BOOK3S_32
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case KVM_INST_MTSRIN:
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if (features & KVM_MAGIC_FEAT_SR) {
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u32 inst_rb = _inst & KVM_MASK_RB;
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kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb);
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}
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break;
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break;
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#endif
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}
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switch (_inst) {
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#ifdef CONFIG_BOOKE
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case KVM_INST_WRTEEI_0:
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@ -245,3 +245,53 @@ kvm_emulate_wrteei_ee_offs:
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.global kvm_emulate_wrteei_len
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kvm_emulate_wrteei_len:
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.long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4
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.global kvm_emulate_mtsrin
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kvm_emulate_mtsrin:
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SCRATCH_SAVE
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LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
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andi. r31, r31, MSR_DR | MSR_IR
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beq kvm_emulate_mtsrin_reg1
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SCRATCH_RESTORE
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kvm_emulate_mtsrin_orig_ins:
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nop
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b kvm_emulate_mtsrin_branch
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kvm_emulate_mtsrin_reg1:
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/* rX >> 26 */
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rlwinm r30,r0,6,26,29
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kvm_emulate_mtsrin_reg2:
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stw r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)
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SCRATCH_RESTORE
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/* Go back to caller */
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kvm_emulate_mtsrin_branch:
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b .
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kvm_emulate_mtsrin_end:
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.global kvm_emulate_mtsrin_branch_offs
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kvm_emulate_mtsrin_branch_offs:
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.long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4
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.global kvm_emulate_mtsrin_reg1_offs
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kvm_emulate_mtsrin_reg1_offs:
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.long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4
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.global kvm_emulate_mtsrin_reg2_offs
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kvm_emulate_mtsrin_reg2_offs:
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.long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4
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.global kvm_emulate_mtsrin_orig_ins_offs
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kvm_emulate_mtsrin_orig_ins_offs:
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.long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4
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.global kvm_emulate_mtsrin_len
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kvm_emulate_mtsrin_len:
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.long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4
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