Patchwork [16/52] KVM: PPC: booke: Paravirtualize wrtee

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Submitter Alexander Graf
Date Jan. 13, 2012, 2:31 p.m.
Message ID <1326465115-5976-17-git-send-email-agraf@suse.de>
Download mbox | patch
Permalink /patch/135895/
State New
Headers show

Comments

Alexander Graf - Jan. 13, 2012, 2:31 p.m.
From: Scott Wood <scottwood@freescale.com>

Also fix wrteei 1 paravirt to check for a pending interrupt.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/kernel/kvm.c      |   92 +++++++++++++++++++++++++++++++++-----
 arch/powerpc/kernel/kvm_emul.S |   96 ++++++++++++++++++++++++++++++---------
 2 files changed, 154 insertions(+), 34 deletions(-)

Patch

diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c
index 2985338..06b15ee 100644
--- a/arch/powerpc/kernel/kvm.c
+++ b/arch/powerpc/kernel/kvm.c
@@ -1,5 +1,6 @@ 
 /*
  * Copyright (C) 2010 SUSE Linux Products GmbH. All rights reserved.
+ * Copyright 2010-2011 Freescale Semiconductor, Inc.
  *
  * Authors:
  *     Alexander Graf <agraf@suse.de>
@@ -29,6 +30,7 @@ 
 #include <asm/sections.h>
 #include <asm/cacheflush.h>
 #include <asm/disassemble.h>
+#include <asm/ppc-opcode.h>
 
 #define KVM_MAGIC_PAGE		(-4096L)
 #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
@@ -41,6 +43,7 @@ 
 #define KVM_INST_B		0x48000000
 #define KVM_INST_B_MASK		0x03ffffff
 #define KVM_INST_B_MAX		0x01ffffff
+#define KVM_INST_LI		0x38000000
 
 #define KVM_MASK_RT		0x03e00000
 #define KVM_RT_30		0x03c00000
@@ -69,6 +72,7 @@ 
 #define KVM_INST_MTMSRD_L1	0x7c010164
 #define KVM_INST_MTMSR		0x7c000124
 
+#define KVM_INST_WRTEE		0x7c000106
 #define KVM_INST_WRTEEI_0	0x7c000146
 #define KVM_INST_WRTEEI_1	0x7c008146
 
@@ -270,26 +274,27 @@  static void kvm_patch_ins_mtmsr(u32 *inst, u32 rt)
 
 #ifdef CONFIG_BOOKE
 
-extern u32 kvm_emulate_wrteei_branch_offs;
-extern u32 kvm_emulate_wrteei_ee_offs;
-extern u32 kvm_emulate_wrteei_len;
-extern u32 kvm_emulate_wrteei[];
+extern u32 kvm_emulate_wrtee_branch_offs;
+extern u32 kvm_emulate_wrtee_reg_offs;
+extern u32 kvm_emulate_wrtee_orig_ins_offs;
+extern u32 kvm_emulate_wrtee_len;
+extern u32 kvm_emulate_wrtee[];
 
-static void kvm_patch_ins_wrteei(u32 *inst)
+static void kvm_patch_ins_wrtee(u32 *inst, u32 rt, int imm_one)
 {
 	u32 *p;
 	int distance_start;
 	int distance_end;
 	ulong next_inst;
 
-	p = kvm_alloc(kvm_emulate_wrteei_len * 4);
+	p = kvm_alloc(kvm_emulate_wrtee_len * 4);
 	if (!p)
 		return;
 
 	/* Find out where we are and put everything there */
 	distance_start = (ulong)p - (ulong)inst;
 	next_inst = ((ulong)inst + 4);
-	distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_branch_offs];
+	distance_end = next_inst - (ulong)&p[kvm_emulate_wrtee_branch_offs];
 
 	/* Make sure we only write valid b instructions */
 	if (distance_start > KVM_INST_B_MAX) {
@@ -298,10 +303,65 @@  static void kvm_patch_ins_wrteei(u32 *inst)
 	}
 
 	/* Modify the chunk to fit the invocation */
-	memcpy(p, kvm_emulate_wrteei, kvm_emulate_wrteei_len * 4);
-	p[kvm_emulate_wrteei_branch_offs] |= distance_end & KVM_INST_B_MASK;
-	p[kvm_emulate_wrteei_ee_offs] |= (*inst & MSR_EE);
-	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_len * 4);
+	memcpy(p, kvm_emulate_wrtee, kvm_emulate_wrtee_len * 4);
+	p[kvm_emulate_wrtee_branch_offs] |= distance_end & KVM_INST_B_MASK;
+
+	if (imm_one) {
+		p[kvm_emulate_wrtee_reg_offs] =
+			KVM_INST_LI | __PPC_RT(30) | MSR_EE;
+	} else {
+		/* Make clobbered registers work too */
+		switch (get_rt(rt)) {
+		case 30:
+			kvm_patch_ins_ll(&p[kvm_emulate_wrtee_reg_offs],
+					 magic_var(scratch2), KVM_RT_30);
+			break;
+		case 31:
+			kvm_patch_ins_ll(&p[kvm_emulate_wrtee_reg_offs],
+					 magic_var(scratch1), KVM_RT_30);
+			break;
+		default:
+			p[kvm_emulate_wrtee_reg_offs] |= rt;
+			break;
+		}
+	}
+
+	p[kvm_emulate_wrtee_orig_ins_offs] = *inst;
+	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrtee_len * 4);
+
+	/* Patch the invocation */
+	kvm_patch_ins_b(inst, distance_start);
+}
+
+extern u32 kvm_emulate_wrteei_0_branch_offs;
+extern u32 kvm_emulate_wrteei_0_len;
+extern u32 kvm_emulate_wrteei_0[];
+
+static void kvm_patch_ins_wrteei_0(u32 *inst)
+{
+	u32 *p;
+	int distance_start;
+	int distance_end;
+	ulong next_inst;
+
+	p = kvm_alloc(kvm_emulate_wrteei_0_len * 4);
+	if (!p)
+		return;
+
+	/* Find out where we are and put everything there */
+	distance_start = (ulong)p - (ulong)inst;
+	next_inst = ((ulong)inst + 4);
+	distance_end = next_inst - (ulong)&p[kvm_emulate_wrteei_0_branch_offs];
+
+	/* Make sure we only write valid b instructions */
+	if (distance_start > KVM_INST_B_MAX) {
+		kvm_patching_worked = false;
+		return;
+	}
+
+	memcpy(p, kvm_emulate_wrteei_0, kvm_emulate_wrteei_0_len * 4);
+	p[kvm_emulate_wrteei_0_branch_offs] |= distance_end & KVM_INST_B_MASK;
+	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_wrteei_0_len * 4);
 
 	/* Patch the invocation */
 	kvm_patch_ins_b(inst, distance_start);
@@ -444,6 +504,11 @@  static void kvm_check_ins(u32 *inst, u32 features)
 	case KVM_INST_MTMSRD_L0:
 		kvm_patch_ins_mtmsr(inst, inst_rt);
 		break;
+#ifdef CONFIG_BOOKE
+	case KVM_INST_WRTEE:
+		kvm_patch_ins_wrtee(inst, inst_rt, 0);
+		break;
+#endif
 	}
 
 	switch (inst_no_rt & ~KVM_MASK_RB) {
@@ -461,8 +526,11 @@  static void kvm_check_ins(u32 *inst, u32 features)
 	switch (_inst) {
 #ifdef CONFIG_BOOKE
 	case KVM_INST_WRTEEI_0:
+		kvm_patch_ins_wrteei_0(inst);
+		break;
+
 	case KVM_INST_WRTEEI_1:
-		kvm_patch_ins_wrteei(inst);
+		kvm_patch_ins_wrtee(inst, 0, 1);
 		break;
 #endif
 	}
diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S
index 3d64c57..801058d 100644
--- a/arch/powerpc/kernel/kvm_emul.S
+++ b/arch/powerpc/kernel/kvm_emul.S
@@ -13,6 +13,7 @@ 
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *
  * Copyright SUSE Linux Products GmbH 2010
+ * Copyright 2010-2011 Freescale Semiconductor, Inc.
  *
  * Authors: Alexander Graf <agraf@suse.de>
  */
@@ -208,24 +209,80 @@  kvm_emulate_mtmsr_orig_ins_offs:
 kvm_emulate_mtmsr_len:
 	.long (kvm_emulate_mtmsr_end - kvm_emulate_mtmsr) / 4
 
+/* also used for wrteei 1 */
+.global kvm_emulate_wrtee
+kvm_emulate_wrtee:
 
+	SCRATCH_SAVE
+
+	/* Fetch old MSR in r31 */
+	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
 
-.global kvm_emulate_wrteei
-kvm_emulate_wrteei:
+	/* Insert new MSR[EE] */
+kvm_emulate_wrtee_reg:
+	ori	r30, r0, 0
+	rlwimi	r31, r30, 0, MSR_EE
+
+	/*
+	 * If MSR[EE] is now set, check for a pending interrupt.
+	 * We could skip this if MSR[EE] was already on, but that
+	 * should be rare, so don't bother.
+	 */
+	andi.	r30, r30, MSR_EE
 
+	/* Put MSR into magic page because we don't call wrtee */
+	STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
+
+	beq	no_wrtee
+
+	/* Check if we have to fetch an interrupt */
+	lwz	r30, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
+	cmpwi	r30, 0
+	bne	do_wrtee
+
+no_wrtee:
+	SCRATCH_RESTORE
+
+	/* Go back to caller */
+kvm_emulate_wrtee_branch:
+	b	.
+
+do_wrtee:
+	SCRATCH_RESTORE
+
+	/* Just fire off the wrtee if it's critical */
+kvm_emulate_wrtee_orig_ins:
+	wrtee	r0
+
+	b	kvm_emulate_wrtee_branch
+
+kvm_emulate_wrtee_end:
+
+.global kvm_emulate_wrtee_branch_offs
+kvm_emulate_wrtee_branch_offs:
+	.long (kvm_emulate_wrtee_branch - kvm_emulate_wrtee) / 4
+
+.global kvm_emulate_wrtee_reg_offs
+kvm_emulate_wrtee_reg_offs:
+	.long (kvm_emulate_wrtee_reg - kvm_emulate_wrtee) / 4
+
+.global kvm_emulate_wrtee_orig_ins_offs
+kvm_emulate_wrtee_orig_ins_offs:
+	.long (kvm_emulate_wrtee_orig_ins - kvm_emulate_wrtee) / 4
+
+.global kvm_emulate_wrtee_len
+kvm_emulate_wrtee_len:
+	.long (kvm_emulate_wrtee_end - kvm_emulate_wrtee) / 4
+
+.global kvm_emulate_wrteei_0
+kvm_emulate_wrteei_0:
 	SCRATCH_SAVE
 
 	/* Fetch old MSR in r31 */
 	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
 
 	/* Remove MSR_EE from old MSR */
-	li	r30, 0
-	ori	r30, r30, MSR_EE
-	andc	r31, r31, r30
-
-	/* OR new MSR_EE onto the old MSR */
-kvm_emulate_wrteei_ee:
-	ori	r31, r31, 0
+	rlwinm	r31, r31, 0, ~MSR_EE
 
 	/* Write new MSR value back */
 	STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
@@ -233,22 +290,17 @@  kvm_emulate_wrteei_ee:
 	SCRATCH_RESTORE
 
 	/* Go back to caller */
-kvm_emulate_wrteei_branch:
+kvm_emulate_wrteei_0_branch:
 	b	.
-kvm_emulate_wrteei_end:
-
-.global kvm_emulate_wrteei_branch_offs
-kvm_emulate_wrteei_branch_offs:
-	.long (kvm_emulate_wrteei_branch - kvm_emulate_wrteei) / 4
-
-.global kvm_emulate_wrteei_ee_offs
-kvm_emulate_wrteei_ee_offs:
-	.long (kvm_emulate_wrteei_ee - kvm_emulate_wrteei) / 4
+kvm_emulate_wrteei_0_end:
 
-.global kvm_emulate_wrteei_len
-kvm_emulate_wrteei_len:
-	.long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4
+.global kvm_emulate_wrteei_0_branch_offs
+kvm_emulate_wrteei_0_branch_offs:
+	.long (kvm_emulate_wrteei_0_branch - kvm_emulate_wrteei_0) / 4
 
+.global kvm_emulate_wrteei_0_len
+kvm_emulate_wrteei_0_len:
+	.long (kvm_emulate_wrteei_0_end - kvm_emulate_wrteei_0) / 4
 
 .global kvm_emulate_mtsrin
 kvm_emulate_mtsrin: