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[Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flush
From: |
Benjamin Herrenschmidt |
Subject: |
[Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts |
Date: |
Sun, 19 Jul 2015 08:20:17 +1000 |
We rework the way the MMU indices are calculated, providing separate
indices for I and D side based on MSR:IR and MSR:DR respectively,
and thus no longer need to flush the TLB on context changes. This also
adds correct support for HV as a separate address space.
Signed-off-by: Benjamin Herrenschmidt <address@hidden>
---
target-ppc/cpu.h | 11 +++++++---
target-ppc/excp_helper.c | 13 ++++--------
target-ppc/helper_regs.h | 54 ++++++++++++++++++++++++++++++++++++++++++------
target-ppc/machine.c | 4 +++-
target-ppc/translate.c | 7 ++++---
5 files changed, 67 insertions(+), 22 deletions(-)
diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index 0a0c47e..04c4885 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -462,6 +462,8 @@ struct ppc_slb_t {
#define MSR_EP 6 /* Exception prefix on 601 */
#define MSR_IR 5 /* Instruction relocate */
#define MSR_DR 4 /* Data relocate */
+#define MSR_IS 5 /* Instruction address space (BookE) */
+#define MSR_DS 4 /* Data address space (BookE) */
#define MSR_PE 3 /* Protection enable on 403 */
#define MSR_PX 2 /* Protection exclusive on 403 x */
#define MSR_PMM 2 /* Performance monitor mark on POWER x */
@@ -505,6 +507,8 @@ struct ppc_slb_t {
#define msr_ep ((env->msr >> MSR_EP) & 1)
#define msr_ir ((env->msr >> MSR_IR) & 1)
#define msr_dr ((env->msr >> MSR_DR) & 1)
+#define msr_is ((env->msr >> MSR_IS) & 1)
+#define msr_ds ((env->msr >> MSR_DS) & 1)
#define msr_pe ((env->msr >> MSR_PE) & 1)
#define msr_px ((env->msr >> MSR_PX) & 1)
#define msr_pmm ((env->msr >> MSR_PMM) & 1)
@@ -944,7 +948,7 @@ struct ppc_segment_page_sizes {
/*****************************************************************************/
/* The whole PowerPC CPU context */
-#define NB_MMU_MODES 3
+#define NB_MMU_MODES 6
#define PPC_CPU_OPCODES_LEN 0x40
#define PPC_CPU_INDIRECT_OPCODES_LEN 0x20
@@ -1107,7 +1111,8 @@ struct CPUPPCState {
/* Those resources are used only in QEMU core */
target_ulong hflags; /* hflags is a MSR & HFLAGS_MASK */
target_ulong hflags_nmsr; /* specific hflags, not coming from MSR */
- int mmu_idx; /* precomputed MMU index to speed up mem accesses */
+ int immu_idx; /* precomputed MMU index to speed up insn access */
+ int dmmu_idx; /* precomputed MMU index to speed up data accesses */
/* Power management */
int (*check_pow)(CPUPPCState *env);
@@ -1249,7 +1254,7 @@ int ppc_dcr_write (ppc_dcr_t *dcr_env, int dcrn, uint32_t
val);
#define MMU_USER_IDX 0
static inline int cpu_mmu_index (CPUPPCState *env, bool ifetch)
{
- return env->mmu_idx;
+ return ifetch ? env->immu_idx : env->dmmu_idx;
}
#include "exec/cpu-all.h"
diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
index b803475..e2f82d2 100644
--- a/target-ppc/excp_helper.c
+++ b/target-ppc/excp_helper.c
@@ -623,9 +623,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int
excp_model, int excp)
if (env->spr[SPR_LPCR] & LPCR_AIL) {
new_msr |= (1 << MSR_IR) | (1 << MSR_DR);
- } else if (msr & ((1 << MSR_IR) | (1 << MSR_DR))) {
- /* If we disactivated any translation, flush TLBs */
- tlb_flush(cs, 1);
}
#ifdef TARGET_PPC64
@@ -675,12 +672,10 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int
excp_model, int excp)
cs->exception_index = POWERPC_EXCP_NONE;
env->error_code = 0;
- if ((env->mmu_model == POWERPC_MMU_BOOKE) ||
- (env->mmu_model == POWERPC_MMU_BOOKE206)) {
- /* XXX: The BookE changes address space when switching modes,
- we should probably implement that as different MMU indexes,
- but for the moment we do it the slow way and flush all. */
- tlb_flush(cs, 1);
+ if (env->mmu_model & POWERPC_MMU_BOOKE) {
+ if ((msr ^ new_msr) & (1u << MSR_GS)) {
+ tlb_flush(cs, 1);
+ }
}
}
diff --git a/target-ppc/helper_regs.h b/target-ppc/helper_regs.h
index 271fddf..70615f1 100644
--- a/target-ppc/helper_regs.h
+++ b/target-ppc/helper_regs.h
@@ -41,11 +41,50 @@ static inline void hreg_swap_gpr_tgpr(CPUPPCState *env)
static inline void hreg_compute_mem_idx(CPUPPCState *env)
{
- /* Precompute MMU index */
- if (msr_pr == 0 && msr_hv != 0) {
- env->mmu_idx = 2;
+ /* This is our encoding for server processors:
+ *
+ * 0 = Guest User space virtual mode
+ * 1 = Guest Kenrel space virtual mode
+ * 2 = Guest Kernel space real mode
+ * 3 = HV User space virtual mode
+ * 4 = HV Kenrel space virtual mode
+ * 5 = HV Kernel space real mode
+ *
+ * The combination PR=1 IR&DR=0 is invalid, we will treat
+ * it as IR=DR=1
+ *
+ * For BookE, we need in theory 8 MMU modes, which would
+ * reduce performance, so instead, we ignore msr_hv and
+ * will flush on HV context switches. We *could* improve
+ * things a bit if needed by using 4 and 5 as HV and flush
+ * only when HV mode changes AS but that complicates things
+ * as we would need to remember which is the current AS mode
+ * for HV for I and D and split more would be hell.
+ *
+ * 0 = AS 0 User space
+ * 1 = AS 0 Kernel space
+ * 2 = AS 1 User space
+ * 3 = AS 1 Kernel space
+ */
+ if (env->mmu_model & POWERPC_MMU_BOOKE) {
+ env->immu_idx = env->dmmu_idx = msr_pr ? 0 : 1;
+ env->immu_idx += msr_is ? 2 : 0;
+ env->dmmu_idx += msr_ds ? 2 : 0;
} else {
- env->mmu_idx = 1 - msr_pr;
+ /* First calucalte a base value independent of HV */
+ if (msr_pr != 0) {
+ /* User space, ignore IR and DR */
+ env->immu_idx = env->dmmu_idx = 0;
+ } else {
+ /* Kernel, setup a base I/D value */
+ env->immu_idx = msr_ir ? 1 : 2;
+ env->dmmu_idx = msr_dr ? 1 : 2;
+ }
+ /* Then offset it for HV */
+ if (msr_hv) {
+ env->immu_idx += 3;
+ env->dmmu_idx += 3;
+ }
}
}
@@ -82,11 +121,14 @@ static inline int hreg_store_msr(CPUPPCState *env,
target_ulong value,
}
if (((value >> MSR_IR) & 1) != msr_ir ||
((value >> MSR_DR) & 1) != msr_dr) {
- /* Flush all tlb when changing translation mode */
- tlb_flush(cs, 1);
excp = POWERPC_EXCP_NONE;
cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
}
+ if ((env->mmu_model & POWERPC_MMU_BOOKE) &&
+ ((value >> MSR_GS) & 1) != msr_gs) {
+ /* Flush all tlb when changing guest mode */
+ tlb_flush(cs, 1);
+ }
if (unlikely((env->flags & POWERPC_FLAG_TGPR) &&
((value ^ env->msr) & (1 << MSR_TGPR)))) {
/* Swap temporary saved registers with GPRs */
diff --git a/target-ppc/machine.c b/target-ppc/machine.c
index f4ac761..b969492 100644
--- a/target-ppc/machine.c
+++ b/target-ppc/machine.c
@@ -90,9 +90,11 @@ static int cpu_load_old(QEMUFile *f, void *opaque, int
version_id)
qemu_get_betls(f, &env->nip);
qemu_get_betls(f, &env->hflags);
qemu_get_betls(f, &env->hflags_nmsr);
- qemu_get_sbe32s(f, &env->mmu_idx);
qemu_get_sbe32(f); /* Discard unused power_mode */
+ /* Ignore saved mmu_idx, recompute */
+ hreg_compute_mem_idx(env);
+
return 0;
}
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 84c5cea..dee0cc8 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -11213,8 +11213,9 @@ void ppc_cpu_dump_state(CPUState *cs, FILE *f,
fprintf_function cpu_fprintf,
env->nip, env->lr, env->ctr, cpu_read_xer(env),
cs->cpu_index);
cpu_fprintf(f, "MSR " TARGET_FMT_lx " HID0 " TARGET_FMT_lx " HF "
- TARGET_FMT_lx " idx %d\n", env->msr, env->spr[SPR_HID0],
- env->hflags, env->mmu_idx);
+ TARGET_FMT_lx " iidx %d didx %d\n",
+ env->msr, env->spr[SPR_HID0],
+ env->hflags, env->immu_idx, env->dmmu_idx);
#if !defined(NO_TIMER_DUMP)
cpu_fprintf(f, "TB %08" PRIu32 " %08" PRIu64
#if !defined(CONFIG_USER_ONLY)
@@ -11423,7 +11424,7 @@ static inline void
gen_intermediate_code_internal(PowerPCCPU *cpu,
ctx.spr_cb = env->spr_cb;
ctx.pr = msr_pr;
ctx.hv = !msr_pr && msr_hv;
- ctx.mem_idx = env->mmu_idx;
+ ctx.mem_idx = env->dmmu_idx;
ctx.insns_flags = env->insns_flags;
ctx.insns_flags2 = env->insns_flags2;
ctx.access_type = -1;
--
2.1.4
- [Qemu-devel] [RFC PATCH 1/4] ppc: Remove MMU_MODEn_SUFFIX definitions, Benjamin Herrenschmidt, 2015/07/18
- [Qemu-devel] [RFC PATCH 4/4] ppc: Do some batching of TCG tlb flushes, Benjamin Herrenschmidt, 2015/07/18
- [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts,
Benjamin Herrenschmidt <=
- Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Aurelien Jarno, 2015/07/19
- Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Benjamin Herrenschmidt, 2015/07/19
- Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Aurelien Jarno, 2015/07/20
- Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts, Benjamin Herrenschmidt, 2015/07/20
[Qemu-devel] [RFC PATCH 2/4] tlb: Add "ifetch" argument to cpu_mmu_index(), Benjamin Herrenschmidt, 2015/07/18