Brandon Potter has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/12309
Change subject: syscall_emul: enhance clone for KvmCPU
......................................................................
syscall_emul: enhance clone for KvmCPU
This patch enables clone to work with the KvmCPU, which will
allow running multi-threaded applications at near hardware
speeds with the KvmCPU model.
Change-Id: I2879e20518bf6c0c19fbc7e11b1583c22b59ef3b
---
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, 33 insertions(+), 2 deletions(-)
diff --git a/src/arch/x86/process.cc b/src/arch/x86/process.cc
index a19ec43..dd47cc1 100644
--- a/src/arch/x86/process.cc
+++ b/src/arch/x86/process.cc
@@ -171,6 +171,9 @@
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;
@@ -210,6 +213,9 @@
{
X86Process::initState();
+ if (useForClone)
+ return;
+
argsInit(PageBytes);
auto p_table = memState->_pTable;
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..d02b5f5 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 +96,10 @@
ReadOnly = 8,
};
+ // flag used by initState to determine when the page table should be
+ // cleared
+ bool shared;
+
virtual void initState(ThreadContext* tc) {};
// for DPRINTF compatibility
diff --git a/src/sim/process.cc b/src/sim/process.cc
index 3a3f66a..7d1a9e2 100644
--- a/src/sim/process.cc
+++ b/src/sim/process.cc
@@ -105,6 +105,7 @@
Process::Process(ProcessParams *params, ObjectFile *obj_file)
: SimObject(params), system(params->system),
kvmInSE(params->kvmInSE),
+ useForClone(false),
objFile(obj_file),
argv(params->cmd), envp(params->env),
host_cwd(checkPathRedirect(params->cwd)), tgt_cwd(params->cwd),
diff --git a/src/sim/process.hh b/src/sim/process.hh
index 35d1c31..182c62e 100644
--- a/src/sim/process.hh
+++ b/src/sim/process.hh
@@ -155,6 +155,11 @@
Stats::Scalar numSyscalls; // track how many system calls are executed
bool kvmInSE; // running KVM requires special initialization
+ /**
+ * Flag used by initState to determine when the page table should be
+ * cleared.
+ */
+ bool useForClone;
ObjectFile *objFile;
std::vector<std::string> argv;
diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index 3f61b59..fc1b7ca 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -1467,6 +1467,8 @@
pp->pid = temp_pid;
pp->ppid = (flags & OS::TGT_CLONE_THREAD) ? p->ppid() : p->pid();
+ pp->useArchPT = p->_params->useArchPT;
+ pp->kvmInSE = p->kvmInSE;
Process *cp = pp->create();
delete pp;
@@ -1487,6 +1489,8 @@
auto child_mem_state = cp->memState;
if (flags & OS::TGT_CLONE_THREAD) {
auto child_p_table = child_mem_state->_pTable;
+ child_p_table->shared = true;
+ cp->useForClone = true;
}
cp->initState();
p->clone(tc, ctc, cp, flags);
@@ -1548,7 +1552,15 @@
ctc->setIntReg(TheISA::SyscallPseudoReturnReg, 1);
#endif
- ctc->pcState(tc->nextInstAddr());
+ if (p->kvmInSE) {
+#if THE_ISA == X86_ISA
+ ctc->pcState(tc->readIntReg(TheISA::INTREG_RCX));
+#else
+ panic("KVM CPU model is not supported in SE mode for this ISA");
+#endif
+ } else {
+ ctc->pcState(tc->nextInstAddr());
+ }
ctc->activate();
return cp->pid();
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I2879e20518bf6c0c19fbc7e11b1583c22b59ef3b
Gerrit-Change-Number: 12309
Gerrit-PatchSet: 1
Gerrit-Owner: Brandon Potter <[email protected]>
Gerrit-Reviewer: Alexandru Duțu <[email protected]>
Gerrit-MessageType: newchange
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