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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [win-pv-devel] [PATCH 2/2] Make the XENBUS_CONSOLE Write method properly synchronous
Have the method directly write into the console ring (and potentially
block). This removes a lot of complexity from the code and makes the
method safe to be called at IRQL > DISPATCH_LEVEL.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
include/console_interface.h | 4 +-
src/xenbus/console.c | 236 +++++++-------------------------------------
2 files changed, 39 insertions(+), 201 deletions(-)
diff --git a/include/console_interface.h b/include/console_interface.h
index bcea6fb..ccbdd30 100644
--- a/include/console_interface.h
+++ b/include/console_interface.h
@@ -67,8 +67,10 @@ typedef VOID
\param Buffer A character buffer
\param Length The length of the buffer
\param CRLF Substitute LF with CRLF
+
+ \return The number of characters written
*/
-typedef NTSTATUS
+typedef ULONG
(*XENBUS_CONSOLE_WRITE)(
IN PINTERFACE Interface,
IN PCHAR Data,
diff --git a/src/xenbus/console.c b/src/xenbus/console.c
index 36e113e..15aea92 100644
--- a/src/xenbus/console.c
+++ b/src/xenbus/console.c
@@ -55,15 +55,11 @@ struct _XENBUS_CONSOLE_CONTEXT {
KSPIN_LOCK Lock;
LONG References;
struct xencons_interface *Shared;
- LIST_ENTRY OutList;
- HIGH_LOCK OutLock;
- KDPC Dpc;
- ULONG Polls;
- ULONG Dpcs;
- ULONG Events;
+ HIGH_LOCK RingLock;
XENBUS_EVTCHN_INTERFACE EvtchnInterface;
PHYSICAL_ADDRESS Address;
PXENBUS_EVTCHN_CHANNEL Channel;
+ ULONG Events;
XENBUS_SUSPEND_INTERFACE SuspendInterface;
XENBUS_DEBUG_INTERFACE DebugInterface;
PXENBUS_SUSPEND_CALLBACK SuspendCallbackEarly;
@@ -96,7 +92,8 @@ static ULONG
ConsoleCopyToRing(
IN PXENBUS_CONSOLE_CONTEXT Context,
IN PCHAR Data,
- IN ULONG Length
+ IN ULONG Length,
+ IN BOOLEAN CRLF
)
{
struct xencons_interface *Shared;
@@ -115,26 +112,31 @@ ConsoleCopyToRing(
Offset = 0;
while (Length != 0) {
+ CHAR Character = Data[Offset];
+ ULONG Required;
ULONG Available;
ULONG Index;
- ULONG CopyLength;
+ Required = (CRLF && Character == '\n') ? 2 : 1;
Available = cons + sizeof (Shared->out) - prod;
- if (Available == 0)
+ if (Available < Required)
break;
Index = MASK_XENCONS_IDX(prod, Shared->out);
- CopyLength = __min(Length, Available);
- CopyLength = __min(CopyLength, sizeof (Shared->out) - Index);
+ if (CRLF && Character == '\n') {
+ Shared->out[Index] = '\r';
+ prod++;
- RtlCopyMemory(&Shared->out[Index], Data + Offset, CopyLength);
+ Index = MASK_XENCONS_IDX(prod, Shared->out);
+ }
- Offset += CopyLength;
- Length -= CopyLength;
+ Shared->out[Index] = Character;
+ prod++;
- prod += CopyLength;
+ Offset++;
+ Length--;
}
KeMemoryBarrier();
@@ -146,128 +148,6 @@ ConsoleCopyToRing(
return Offset;
}
-static FORCEINLINE PXENBUS_CONSOLE_BUFFER
-__ConsoleGetHeadBuffer(
- IN PXENBUS_CONSOLE_CONTEXT Context
- )
-{
- PLIST_ENTRY ListEntry;
- PXENBUS_CONSOLE_BUFFER Buffer;
- KIRQL Irql;
-
- AcquireHighLock(&Context->OutLock, &Irql);
- ListEntry = (!IsListEmpty(&Context->OutList)) ?
- Context->OutList.Flink :
- NULL;
- ReleaseHighLock(&Context->OutLock, Irql);
-
- if (ListEntry == NULL)
- return NULL;
-
- Buffer = CONTAINING_RECORD(ListEntry,
- XENBUS_CONSOLE_BUFFER,
- ListEntry);
-
- return Buffer;
-}
-
-static FORCEINLINE VOID
-__ConsoleRemoveHeadBuffer(
- IN PXENBUS_CONSOLE_CONTEXT Context
- )
-{
- KIRQL Irql;
-
- AcquireHighLock(&Context->OutLock, &Irql);
- (VOID) RemoveHeadList(&Context->OutList);
- ReleaseHighLock(&Context->OutLock, Irql);
-}
-
-static FORCEINLINE VOID
-__ConsoleAddTailBuffer(
- IN PXENBUS_CONSOLE_CONTEXT Context,
- IN PXENBUS_CONSOLE_BUFFER Buffer
- )
-{
- KIRQL Irql;
-
- AcquireHighLock(&Context->OutLock, &Irql);
- InsertTailList(&Context->OutList, &Buffer->ListEntry);
- ReleaseHighLock(&Context->OutLock, Irql);
-}
-
-static BOOLEAN
-ConsoleOut(
- IN PXENBUS_CONSOLE_CONTEXT Context
- )
-{
- PXENBUS_CONSOLE_BUFFER Buffer;
- ULONG Written;
-
- Buffer = __ConsoleGetHeadBuffer(Context);
-
- if (Buffer == NULL)
- return FALSE;
-
- Written = ConsoleCopyToRing(Context,
- Buffer->Data + Buffer->Offset,
- Buffer->Length - Buffer->Offset);
-
- Buffer->Offset += Written;
-
- ASSERT3U(Buffer->Offset, <=, Buffer->Length);
- if (Buffer->Offset == Buffer->Length) {
- __ConsoleRemoveHeadBuffer(Context);
- __ConsoleFree(Buffer);
- }
-
- if (Written != 0)
- XENBUS_EVTCHN(Send,
- &Context->EvtchnInterface,
- Context->Channel);
-
- return TRUE;
-}
-
-static VOID
-ConsoleFlush(
- IN PXENBUS_CONSOLE_CONTEXT Context
- )
-{
- for (;;) {
- if (!ConsoleOut(Context))
- break;
- }
-}
-
-static
-_Function_class_(KDEFERRED_ROUTINE)
-_IRQL_requires_max_(DISPATCH_LEVEL)
-_IRQL_requires_min_(DISPATCH_LEVEL)
-_IRQL_requires_(DISPATCH_LEVEL)
-_IRQL_requires_same_
-VOID
-ConsoleDpc(
- IN PKDPC Dpc,
- IN PVOID _Context,
- IN PVOID Argument1,
- IN PVOID Argument2
- )
-{
- PXENBUS_CONSOLE_CONTEXT Context = _Context;
-
- UNREFERENCED_PARAMETER(Dpc);
- UNREFERENCED_PARAMETER(Argument1);
- UNREFERENCED_PARAMETER(Argument2);
-
- ASSERT(Context != NULL);
-
- KeAcquireSpinLockAtDpcLevel(&Context->Lock);
- if (Context->References != 0)
- (VOID) ConsoleOut(Context);
- KeReleaseSpinLockFromDpcLevel(&Context->Lock);
-}
-
static
_Function_class_(KSERVICE_ROUTINE)
_IRQL_requires_(HIGH_LEVEL)
@@ -286,9 +166,6 @@ ConsoleEvtchnCallback(
Context->Events++;
- if (KeInsertQueueDpc(&Context->Dpc, NULL, NULL))
- Context->Dpcs++;
-
return TRUE;
}
@@ -341,10 +218,6 @@ ConsoleEnable(
LogPrintf(LOG_LEVEL_INFO,
"CONSOLE: ENABLE (%u)\n",
Port);
-
- // Trigger an initial poll
- if (KeInsertQueueDpc(&Context->Dpc, NULL, NULL))
- Context->Dpcs++;
}
static PHYSICAL_ADDRESS
@@ -436,13 +309,11 @@ ConsoleDebugCallback(
XENBUS_DEBUG(Printf,
&Context->DebugInterface,
- "Events = %lu Dpcs = %lu Polls = %lu\n",
- Context->Events,
- Context->Dpcs,
- Context->Polls);
+ "Events = %lu\n",
+ Context->Events);
}
-static NTSTATUS
+static ULONG
ConsoleWrite(
IN PINTERFACE Interface,
IN PCHAR Data,
@@ -451,50 +322,29 @@ ConsoleWrite(
)
{
PXENBUS_CONSOLE_CONTEXT Context = Interface->Context;
- ULONG Extra;
- PXENBUS_CONSOLE_BUFFER Buffer;
- ULONG Index;
KIRQL Irql;
+ ULONG Written;
NTSTATUS status;
- Extra = 0;
- if (CRLF) {
- for (Index = 0; Index < Length; Index++) {
- if (Data[Index] == '\n')
- Extra++;
- }
- }
+ AcquireHighLock(&Context->RingLock, &Irql);
- Buffer = __ConsoleAllocate(FIELD_OFFSET(XENBUS_CONSOLE_BUFFER, Data) +
- Length + Extra);
+ Written = 0;
- status = STATUS_NO_MEMORY;
- if (Buffer == NULL)
- goto fail1;
-
- Index = 0;
- while (Index < Length + Extra) {
- if (CRLF && *Data == '\n')
- Buffer->Data[Index++] = '\r';
-
- Buffer->Data[Index++] = *Data++;
- }
-
- Buffer->Length = Length + Extra;
-
- AcquireHighLock(&Context->OutLock, &Irql);
- InsertTailList(&Context->OutList, &Buffer->ListEntry);
- ReleaseHighLock(&Context->OutLock, Irql);
+ status = STATUS_UNSUCCESSFUL;
+ if (!Context->Enabled)
+ goto done;
- if (KeInsertQueueDpc(&Context->Dpc, NULL, NULL))
- Context->Dpcs++;
+ Written += ConsoleCopyToRing(Context, Data, Length, CRLF);
- return STATUS_SUCCESS;
+ if (Written != 0)
+ XENBUS_EVTCHN(Send,
+ &Context->EvtchnInterface,
+ Context->Channel);
-fail1:
- Error("fail1 (%08x)\n", status);
+done:
+ ReleaseHighLock(&Context->RingLock, Irql);
- return status;
+ return Written;
}
static NTSTATUS
@@ -635,8 +485,6 @@ ConsoleRelease(
Trace("====>\n");
- ConsoleFlush(Context);
-
XENBUS_DEBUG(Deregister,
&Context->DebugInterface,
Context->DebugCallback);
@@ -716,11 +564,7 @@ ConsoleInitialize(
ASSERT((*Context)->DebugInterface.Interface.Context != NULL);
KeInitializeSpinLock(&(*Context)->Lock);
-
- InitializeListHead(&(*Context)->OutList);
- InitializeHighLock(&(*Context)->OutLock);
-
- KeInitializeDpc(&(*Context)->Dpc, ConsoleDpc, *Context);
+ InitializeHighLock(&(*Context)->RingLock);
(*Context)->Fdo = Fdo;
@@ -788,20 +632,12 @@ ConsoleTeardown(
Trace("====>\n");
ASSERT3U(KeGetCurrentIrql(), ==, PASSIVE_LEVEL);
- KeFlushQueuedDpcs();
- Context->Polls = 0;
- Context->Dpcs = 0;
Context->Events = 0;
Context->Fdo = NULL;
- RtlZeroMemory(&Context->Dpc, sizeof (KDPC));
-
- RtlZeroMemory(&Context->OutLock, sizeof (HIGH_LOCK));
- ASSERT(IsListEmpty(&Context->OutList));
- RtlZeroMemory(&Context->OutList, sizeof (LIST_ENTRY));
-
+ RtlZeroMemory(&Context->RingLock, sizeof (HIGH_LOCK));
RtlZeroMemory(&Context->Lock, sizeof (KSPIN_LOCK));
RtlZeroMemory(&Context->DebugInterface,
--
2.5.3
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