Alexandru Duțu has submitted this change and it was merged. (
https://gem5-review.googlesource.com/c/public/gem5/+/18268 )
Change subject: sim-se: Enhance clone for X86KvmCPU
......................................................................
sim-se: Enhance clone for X86KvmCPU
This changeset enables clone to work with X86KvmCPU model, which
will allow running multi-threaded applications at near hardware
speeds. Even though the application is multi-threaded, the KvmCPU
model uses one event queue, therefore, only one hardware thread
will be used, through KVM, to simulate multiple application threads.
Change-Id: I2b2a7b1edb1c56eeb9c4fa0553cd236029cd53f8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18268
Reviewed-by: Jason Lowe-Power <[email protected]>
Maintainer: Jason Lowe-Power <[email protected]>
Tested-by: kokoro <[email protected]>
---
M src/arch/x86/process.cc
M src/mem/multi_level_page_table.hh
M src/mem/page_table.hh
M src/sim/process.cc
M src/sim/process.hh
M src/sim/syscall_emul.hh
6 files changed, 37 insertions(+), 6 deletions(-)
Approvals:
Jason Lowe-Power: Looks good to me, approved; Looks good to me, approved
kokoro: Regressions pass
diff --git a/src/arch/x86/process.cc b/src/arch/x86/process.cc
index 04bc0dd..9e34a7b 100644
--- a/src/arch/x86/process.cc
+++ b/src/arch/x86/process.cc
@@ -165,6 +165,9 @@
SyscallDesc *_syscallDescs, int _numSyscallDescs)
: X86Process(params, objFile, _syscallDescs, _numSyscallDescs)
{
+ if (kvmInSE)
+ panic("KVM CPU model does not support 32 bit processes");
+
_gdtStart = ULL(0xffffd000);
_gdtSize = PageBytes;
@@ -197,6 +200,9 @@
{
X86Process::initState();
+ if (useForClone)
+ return;
+
argsInit(PageBytes);
// Set up the vsyscall page for this process.
diff --git a/src/mem/multi_level_page_table.hh
b/src/mem/multi_level_page_table.hh
index bd40d37..f517eaf 100644
--- a/src/mem/multi_level_page_table.hh
+++ b/src/mem/multi_level_page_table.hh
@@ -204,6 +204,9 @@
void
initState(ThreadContext* tc) override
{
+ if (shared)
+ return;
+
_basePtr = prepTopTable<EntryTypes...>(system, pageSize);
}
diff --git a/src/mem/page_table.hh b/src/mem/page_table.hh
index 447d3a5..03e18c2 100644
--- a/src/mem/page_table.hh
+++ b/src/mem/page_table.hh
@@ -75,7 +75,7 @@
EmulationPageTable(
const std::string &__name, uint64_t _pid, Addr _pageSize) :
pageSize(_pageSize), offsetMask(mask(floorLog2(_pageSize))),
- _pid(_pid), _name(__name)
+ _pid(_pid), _name(__name), shared(false)
{
assert(isPowerOf2(pageSize));
}
@@ -96,6 +96,9 @@
ReadOnly = 8,
};
+ // flag which marks the page table as shared among software threads
+ bool shared;
+
virtual void initState(ThreadContext* tc) {};
// for DPRINTF compatibility
diff --git a/src/sim/process.cc b/src/sim/process.cc
index c4dd641..5cec295 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -106,6 +106,7 @@
: SimObject(params), system(params->system),
useArchPT(params->useArchPT),
kvmInSE(params->kvmInSE),
+ useForClone(false),
pTable(pTable),
initVirtMem(system->getSystemPort(), this,
SETranslatingPortProxy::Always),
diff --git a/src/sim/process.hh b/src/sim/process.hh
index c690e82..a1ca84b 100644
--- a/src/sim/process.hh
+++ b/src/sim/process.hh
@@ -172,8 +172,12 @@
Stats::Scalar numSyscalls; // track how many system calls are executed
- bool useArchPT; // flag for using architecture specific page table
- bool kvmInSE; // running KVM requires special initialization
+ // flag for using architecture specific page table
+ bool useArchPT;
+ // running KVM requires special initialization
+ bool kvmInSE;
+ // flag for using the process as a thread which shares page tables
+ bool useForClone;
EmulationPageTable *pTable;
diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index 0378bd7..87c16c4 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1551,6 +1551,8 @@
pp->pid = temp_pid;
pp->ppid = (flags & OS::TGT_CLONE_THREAD) ? p->ppid() : p->pid();
+ pp->useArchPT = p->useArchPT;
+ pp->kvmInSE = p->kvmInSE;
Process *cp = pp->create();
delete pp;
@@ -1566,6 +1568,10 @@
ptidBuf.copyOut(tc->getMemProxy());
}
+ if (flags & OS::TGT_CLONE_THREAD) {
+ cp->pTable->shared = true;
+ cp->useForClone = true;
+ }
cp->initState();
p->clone(tc, ctc, cp, flags);
@@ -1599,9 +1605,17 @@
ctc->setIntReg(TheISA::SyscallPseudoReturnReg, 1);
#endif
- TheISA::PCState cpc = tc->pcState();
- cpc.advance();
- ctc->pcState(cpc);
+ if (p->kvmInSE) {
+#if THE_ISA == X86_ISA
+ ctc->pcState(tc->readIntReg(TheISA::INTREG_RCX));
+#else
+ panic("KVM CPU model is not supported for this ISA");
+#endif
+ } else {
+ TheISA::PCState cpc = tc->pcState();
+ cpc.advance();
+ ctc->pcState(cpc);
+ }
ctc->activate();
return cp->pid();
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I2b2a7b1edb1c56eeb9c4fa0553cd236029cd53f8
Gerrit-Change-Number: 18268
Gerrit-PatchSet: 4
Gerrit-Owner: Alexandru Duțu <[email protected]>
Gerrit-Reviewer: Alexandru Duțu <[email protected]>
Gerrit-Reviewer: Jason Lowe-Power <[email protected]>
Gerrit-Reviewer: kokoro <[email protected]>
Gerrit-MessageType: merged
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