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-rw-r--r--src/cpu/kvm/X86KvmCPU.py2
-rw-r--r--src/cpu/kvm/x86_cpu.cc287
-rw-r--r--src/cpu/kvm/x86_cpu.hh36
3 files changed, 300 insertions, 25 deletions
diff --git a/src/cpu/kvm/X86KvmCPU.py b/src/cpu/kvm/X86KvmCPU.py
index 0b12da676..18a4d3d6f 100644
--- a/src/cpu/kvm/X86KvmCPU.py
+++ b/src/cpu/kvm/X86KvmCPU.py
@@ -43,3 +43,5 @@ class X86KvmCPU(BaseKvmCPU):
void dumpXSave();
void dumpVCpuEvents();
''')
+
+ useXSave = Param.Bool(True, "Use XSave to synchronize FPU/SIMD registers")
diff --git a/src/cpu/kvm/x86_cpu.cc b/src/cpu/kvm/x86_cpu.cc
index 1208bf2ec..8f7ca19e4 100644
--- a/src/cpu/kvm/x86_cpu.cc
+++ b/src/cpu/kvm/x86_cpu.cc
@@ -67,6 +67,38 @@ using namespace X86ISA;
// data) is used to indicate that a segment has been accessed.
#define SEG_TYPE_BIT_ACCESSED 1
+struct FXSave
+{
+ uint16_t fcw;
+ uint16_t fsw;
+ uint8_t ftwx;
+ uint8_t pad0;
+ uint16_t last_opcode;
+ union {
+ struct {
+ uint32_t fpu_ip;
+ uint16_t fpu_cs;
+ uint16_t pad1;
+ uint32_t fpu_dp;
+ uint16_t fpu_ds;
+ uint16_t pad2;
+ } ctrl32;
+
+ struct {
+ uint64_t fpu_ip;
+ uint64_t fpu_dp;
+ } ctrl64;
+ };
+ uint32_t mxcsr;
+ uint32_t mxcsr_mask;
+
+ uint8_t fpr[8][16];
+ uint8_t xmm[16][16];
+
+ uint64_t reserved[12];
+} M5_ATTR_PACKED;
+
+static_assert(sizeof(FXSave) == 512, "Unexpected size of FXSave");
#define FOREACH_IREG() \
do { \
@@ -208,23 +240,61 @@ dumpKvm(const struct kvm_debugregs &regs)
#endif
static void
-dumpKvm(const struct kvm_fpu &fpu)
+dumpFpuSpec(const struct FXSave &xs)
{
- inform("FPU registers:\n");
+ inform("\tlast_ip: 0x%x\n", xs.ctrl64.fpu_ip);
+ inform("\tlast_dp: 0x%x\n", xs.ctrl64.fpu_dp);
+ inform("\tmxcsr_mask: 0x%x\n", xs.mxcsr_mask);
+}
+
+static void
+dumpFpuSpec(const struct kvm_fpu &fpu)
+{
+ inform("\tlast_ip: 0x%x\n", fpu.last_ip);
+ inform("\tlast_dp: 0x%x\n", fpu.last_dp);
+}
+
+template<typename T>
+static void
+dumpFpuCommon(const T &fpu)
+{
+ const unsigned top((fpu.fsw >> 11) & 0x7);
inform("\tfcw: 0x%x\n", fpu.fcw);
- inform("\tfsw: 0x%x\n", fpu.fsw);
+
+ inform("\tfsw: 0x%x (top: %i, "
+ "conditions: %s%s%s%s, exceptions: %s%s%s%s%s%s %s%s%s)\n",
+ fpu.fsw, top,
+
+ (fpu.fsw & CC0Bit) ? "C0" : "",
+ (fpu.fsw & CC1Bit) ? "C1" : "",
+ (fpu.fsw & CC2Bit) ? "C2" : "",
+ (fpu.fsw & CC3Bit) ? "C3" : "",
+
+ (fpu.fsw & IEBit) ? "I" : "",
+ (fpu.fsw & DEBit) ? "D" : "",
+ (fpu.fsw & ZEBit) ? "Z" : "",
+ (fpu.fsw & OEBit) ? "O" : "",
+ (fpu.fsw & UEBit) ? "U" : "",
+ (fpu.fsw & PEBit) ? "P" : "",
+
+ (fpu.fsw & StackFaultBit) ? "SF " : "",
+ (fpu.fsw & ErrSummaryBit) ? "ES " : "",
+ (fpu.fsw & BusyBit) ? "BUSY " : ""
+ );
inform("\tftwx: 0x%x\n", fpu.ftwx);
inform("\tlast_opcode: 0x%x\n", fpu.last_opcode);
- inform("\tlast_ip: 0x%x\n", fpu.last_ip);
- inform("\tlast_dp: 0x%x\n", fpu.last_dp);
+ dumpFpuSpec(fpu);
inform("\tmxcsr: 0x%x\n", fpu.mxcsr);
inform("\tFP Stack:\n");
for (int i = 0; i < 8; ++i) {
- const bool empty(!((fpu.ftwx >> i) & 0x1));
+ const unsigned reg_idx((i + top) & 0x7);
+ const bool empty(!((fpu.ftwx >> reg_idx) & 0x1));
+ const double value(X86ISA::loadFloat80(fpu.fpr[i]));
char hex[33];
- for (int j = 0; j < 16; ++j)
+ for (int j = 0; j < 10; ++j)
snprintf(&hex[j*2], 3, "%.2x", fpu.fpr[i][j]);
- inform("\t\t%i: 0x%s%s\n", i, hex, empty ? " (e)" : "");
+ inform("\t\tST%i/%i: 0x%s (%f)%s\n", i, reg_idx,
+ hex, value, empty ? " (e)" : "");
}
inform("\tXMM registers:\n");
for (int i = 0; i < 16; ++i) {
@@ -236,6 +306,20 @@ dumpKvm(const struct kvm_fpu &fpu)
}
static void
+dumpKvm(const struct kvm_fpu &fpu)
+{
+ inform("FPU registers:\n");
+ dumpFpuCommon(fpu);
+}
+
+static void
+dumpKvm(const struct kvm_xsave &xsave)
+{
+ inform("FPU registers (XSave):\n");
+ dumpFpuCommon(*(FXSave *)xsave.region);
+}
+
+static void
dumpKvm(const struct kvm_msrs &msrs)
{
inform("MSRs:\n");
@@ -261,15 +345,6 @@ dumpKvm(const struct kvm_xcrs &regs)
}
static void
-dumpKvm(const struct kvm_xsave &xsave)
-{
- inform("KVM XSAVE:\n");
-
- Trace::dump((Tick)-1, "xsave.region",
- xsave.region, sizeof(xsave.region));
-}
-
-static void
dumpKvm(const struct kvm_vcpu_events &events)
{
inform("vCPU events:\n");
@@ -441,7 +516,8 @@ checkSeg(const char *name, const int idx, const struct kvm_segment &seg,
}
X86KvmCPU::X86KvmCPU(X86KvmCPUParams *params)
- : BaseKvmCPU(params)
+ : BaseKvmCPU(params),
+ useXSave(params->useXSave)
{
Kvm &kvm(vm.kvm);
@@ -457,6 +533,14 @@ X86KvmCPU::X86KvmCPU(X86KvmCPUParams *params)
haveDebugRegs = kvm.capDebugRegs();
haveXSave = kvm.capXSave();
haveXCRs = kvm.capXCRs();
+
+ if (useXSave && !haveXSave) {
+ warn("KVM: XSAVE not supported by host. MXCSR synchronization might be "
+ "unreliable due to kernel bugs.\n");
+ useXSave = false;
+ } else if (!useXSave) {
+ warn("KVM: XSave FPU/SIMD synchronization disabled by user.\n");
+ }
}
X86KvmCPU::~X86KvmCPU()
@@ -483,13 +567,15 @@ void
X86KvmCPU::dump()
{
dumpIntRegs();
- dumpFpuRegs();
+ if (useXSave)
+ dumpXSave();
+ else
+ dumpFpuRegs();
dumpSpecRegs();
dumpDebugRegs();
dumpXCRs();
dumpVCpuEvents();
dumpMSRs();
- dumpXSave();
}
void
@@ -729,10 +815,100 @@ X86KvmCPU::updateKvmStateSRegs()
setSpecialRegisters(sregs);
}
+
+template <typename T>
+static void
+updateKvmStateFPUCommon(ThreadContext *tc, T &fpu)
+{
+ static_assert(sizeof(X86ISA::FloatRegBits) == 8,
+ "Unexpected size of X86ISA::FloatRegBits");
+
+ fpu.mxcsr = tc->readMiscRegNoEffect(MISCREG_MXCSR);
+ fpu.fcw = tc->readMiscRegNoEffect(MISCREG_FCW);
+ // No need to rebuild from MISCREG_FSW and MISCREG_TOP if we read
+ // with effects.
+ fpu.fsw = tc->readMiscReg(MISCREG_FSW);
+
+ uint64_t ftw(tc->readMiscRegNoEffect(MISCREG_FTW));
+ fpu.ftwx = X86ISA::convX87TagsToXTags(ftw);
+
+ fpu.last_opcode = tc->readMiscRegNoEffect(MISCREG_FOP);
+
+ const unsigned top((fpu.fsw >> 11) & 0x7);
+ for (int i = 0; i < 8; ++i) {
+ const unsigned reg_idx((i + top) & 0x7);
+ const double value(tc->readFloatReg(FLOATREG_FPR(reg_idx)));
+ DPRINTF(KvmContext, "Setting KVM FP reg %i (st[%i]) := %f\n",
+ reg_idx, i, value);
+ X86ISA::storeFloat80(fpu.fpr[i], value);
+ }
+
+ // TODO: We should update the MMX state
+
+ for (int i = 0; i < 16; ++i) {
+ *(X86ISA::FloatRegBits *)&fpu.xmm[i][0] =
+ tc->readFloatRegBits(FLOATREG_XMM_LOW(i));
+ *(X86ISA::FloatRegBits *)&fpu.xmm[i][8] =
+ tc->readFloatRegBits(FLOATREG_XMM_HIGH(i));
+ }
+}
+
+void
+X86KvmCPU::updateKvmStateFPULegacy()
+{
+ struct kvm_fpu fpu;
+
+ // There is some padding in the FP registers, so we'd better zero
+ // the whole struct.
+ memset(&fpu, 0, sizeof(fpu));
+
+ updateKvmStateFPUCommon(tc, fpu);
+
+ if (tc->readMiscRegNoEffect(MISCREG_FISEG))
+ warn_once("MISCREG_FISEG is non-zero.\n");
+
+ fpu.last_ip = tc->readMiscRegNoEffect(MISCREG_FIOFF);
+
+ if (tc->readMiscRegNoEffect(MISCREG_FOSEG))
+ warn_once("MISCREG_FOSEG is non-zero.\n");
+
+ fpu.last_dp = tc->readMiscRegNoEffect(MISCREG_FOOFF);
+
+ setFPUState(fpu);
+}
+
+void
+X86KvmCPU::updateKvmStateFPUXSave()
+{
+ struct kvm_xsave kxsave;
+ FXSave &xsave(*(FXSave *)kxsave.region);
+
+ // There is some padding and reserved fields in the structure, so
+ // we'd better zero the whole thing.
+ memset(&kxsave, 0, sizeof(kxsave));
+
+ updateKvmStateFPUCommon(tc, xsave);
+
+ if (tc->readMiscRegNoEffect(MISCREG_FISEG))
+ warn_once("MISCREG_FISEG is non-zero.\n");
+
+ xsave.ctrl64.fpu_ip = tc->readMiscRegNoEffect(MISCREG_FIOFF);
+
+ if (tc->readMiscRegNoEffect(MISCREG_FOSEG))
+ warn_once("MISCREG_FOSEG is non-zero.\n");
+
+ xsave.ctrl64.fpu_dp = tc->readMiscRegNoEffect(MISCREG_FOOFF);
+
+ setXSave(kxsave);
+}
+
void
X86KvmCPU::updateKvmStateFPU()
{
- warn_once("X86KvmCPU::updateKvmStateFPU not implemented\n");
+ if (useXSave)
+ updateKvmStateFPUXSave();
+ else
+ updateKvmStateFPULegacy();
}
void
@@ -766,7 +942,10 @@ X86KvmCPU::updateThreadContext()
updateThreadContextRegs();
updateThreadContextSRegs();
- updateThreadContextFPU();
+ if (useXSave)
+ updateThreadContextXSave();
+ else
+ updateThreadContextFPU();
updateThreadContextMSRs();
// The M5 misc reg caches some values from other
@@ -851,10 +1030,72 @@ X86KvmCPU::updateThreadContextSRegs()
#undef APPLY_DTABLE
}
+template<typename T>
+static void
+updateThreadContextFPUCommon(ThreadContext *tc, const T &fpu)
+{
+ const unsigned top((fpu.fsw >> 11) & 0x7);
+
+ static_assert(sizeof(X86ISA::FloatRegBits) == 8,
+ "Unexpected size of X86ISA::FloatRegBits");
+
+ for (int i = 0; i < 8; ++i) {
+ const unsigned reg_idx((i + top) & 0x7);
+ const double value(X86ISA::loadFloat80(fpu.fpr[i]));
+ DPRINTF(KvmContext, "Setting gem5 FP reg %i (st[%i]) := %f\n",
+ reg_idx, i, value);
+ tc->setFloatReg(FLOATREG_FPR(reg_idx), value);
+ }
+
+ // TODO: We should update the MMX state
+
+ tc->setMiscRegNoEffect(MISCREG_X87_TOP, top);
+ tc->setMiscRegNoEffect(MISCREG_MXCSR, fpu.mxcsr);
+ tc->setMiscRegNoEffect(MISCREG_FCW, fpu.fcw);
+ tc->setMiscRegNoEffect(MISCREG_FSW, fpu.fsw);
+
+ uint64_t ftw(convX87XTagsToTags(fpu.ftwx));
+ // TODO: Are these registers really the same?
+ tc->setMiscRegNoEffect(MISCREG_FTW, ftw);
+ tc->setMiscRegNoEffect(MISCREG_FTAG, ftw);
+
+ tc->setMiscRegNoEffect(MISCREG_FOP, fpu.last_opcode);
+
+ for (int i = 0; i < 16; ++i) {
+ tc->setFloatRegBits(FLOATREG_XMM_LOW(i),
+ *(X86ISA::FloatRegBits *)&fpu.xmm[i][0]);
+ tc->setFloatRegBits(FLOATREG_XMM_HIGH(i),
+ *(X86ISA::FloatRegBits *)&fpu.xmm[i][8]);
+ }
+}
+
void
X86KvmCPU::updateThreadContextFPU()
{
- warn_once("X86KvmCPU::updateThreadContextFPU not implemented\n");
+ struct kvm_fpu fpu;
+ getFPUState(fpu);
+
+ updateThreadContextFPUCommon(tc, fpu);
+
+ tc->setMiscRegNoEffect(MISCREG_FISEG, 0);
+ tc->setMiscRegNoEffect(MISCREG_FIOFF, fpu.last_ip);
+ tc->setMiscRegNoEffect(MISCREG_FOSEG, 0);
+ tc->setMiscRegNoEffect(MISCREG_FOOFF, fpu.last_dp);
+}
+
+void
+X86KvmCPU::updateThreadContextXSave()
+{
+ struct kvm_xsave kxsave;
+ FXSave &xsave(*(FXSave *)kxsave.region);
+ getXSave(kxsave);
+
+ updateThreadContextFPUCommon(tc, xsave);
+
+ tc->setMiscRegNoEffect(MISCREG_FISEG, 0);
+ tc->setMiscRegNoEffect(MISCREG_FIOFF, xsave.ctrl64.fpu_ip);
+ tc->setMiscRegNoEffect(MISCREG_FOSEG, 0);
+ tc->setMiscRegNoEffect(MISCREG_FOOFF, xsave.ctrl64.fpu_dp);
}
void
diff --git a/src/cpu/kvm/x86_cpu.hh b/src/cpu/kvm/x86_cpu.hh
index 602fc8416..7dacdb03f 100644
--- a/src/cpu/kvm/x86_cpu.hh
+++ b/src/cpu/kvm/x86_cpu.hh
@@ -171,8 +171,33 @@ class X86KvmCPU : public BaseKvmCPU
void updateKvmStateRegs();
/** Update control registers (CRx, segments, etc.) */
void updateKvmStateSRegs();
- /** Update FPU and SIMD registers */
+ /**
+ * Update FPU and SIMD registers
+ *
+ * This method uses the appropriate (depending on availability and
+ * user configuration) kernel API by calling
+ * updateKvmStateFPULegacy() or updateKvmStateFPUXSave().
+ *
+ * @see updateKvmStateFPULegacy()
+ * @see updateKvmStateFPUXSave()
+ */
void updateKvmStateFPU();
+ /**
+ * Update FPU and SIMD registers using the legacy API
+ *
+ * @note This method should normally only be called by
+ * updateKvmStateFPU() which automatically chooses between
+ * available APIs.
+ */
+ void updateKvmStateFPULegacy();
+ /**
+ * Update FPU and SIMD registers using the XSave API
+ *
+ * @note This method should normally only be called by
+ * updateKvmStateFPU() which automatically chooses between
+ * available APIs.
+ */
+ void updateKvmStateFPUXSave();
/** Update MSR registers */
void updateKvmStateMSRs();
/** @} */
@@ -187,8 +212,10 @@ class X86KvmCPU : public BaseKvmCPU
void updateThreadContextRegs();
/** Update control registers (CRx, segments, etc.) */
void updateThreadContextSRegs();
- /** Update FPU and SIMD registers */
+ /** Update FPU and SIMD registers using the legacy API */
void updateThreadContextFPU();
+ /** Update FPU and SIMD registers using the XSave API */
+ void updateThreadContextXSave();
/** Update MSR registers */
void updateThreadContextMSRs();
/** @} */
@@ -217,6 +244,11 @@ class X86KvmCPU : public BaseKvmCPU
bool haveDebugRegs;
/** Kvm::capXSave() available? */
bool haveXSave;
+ /**
+ * Should the XSave interface be used to sync the FPU and SIMD
+ * registers?
+ */
+ bool useXSave;
/** Kvm::capXCRs() available? */
bool haveXCRs;
/** @} */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-15 17:11:54 +0000