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

Alexander Graf
2012-01-13T14:58:38Z

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(-)

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:
--
1.6.0.2