I'm looking at adding support for writeable files to qemu's fw_cfg, and this would be necessary to write them.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: David Woodhouse <david.woodho...@intel.com>
---
OvmfPkg/Include/Library/QemuFwCfgLib.h | 19 +++++++++
OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S | 20 ++++++++++
OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm | 22 +++++++++++
OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c | 49 ++++++++++++++++++++++++
OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.S | 17 ++++++++
OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.asm | 20 ++++++++++
6 files changed, 147 insertions(+)
diff --git a/OvmfPkg/Include/Library/QemuFwCfgLib.h
b/OvmfPkg/Include/Library/QemuFwCfgLib.h
index 3776d79..bbe3fd7 100644
--- a/OvmfPkg/Include/Library/QemuFwCfgLib.h
+++ b/OvmfPkg/Include/Library/QemuFwCfgLib.h
@@ -103,6 +103,25 @@ QemuFwCfgReadBytes (
/**
+ Writes firmware configuration bytes from a buffer
+
+ If called multiple times, then the data written will
+ continue at the offset of the firmware configuration
+ item where the previous write ended.
+
+ @param[in] Size - Size in bytes to write
+ @param[in] Buffer - Buffer to read data from
+
+**/
+VOID
+EFIAPI
+QemuFwCfgWriteBytes (
+ IN UINTN Size,
+ IN VOID *Buffer
+ );
+
+
+/**
Reads a UINT8 firmware configuration value
@return Value of Firmware Configuration item read
diff --git a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
index a32b2c6..286c28f 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
+++ b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.S
@@ -30,3 +30,23 @@ rep insb
popl %edi
ret
+
+#------------------------------------------------------------------------------
+# VOID
+# EFIAPI
+# IoWriteFifo8 (
+# IN UINTN Port,
+# IN UINTN Size,
+# IN VOID *Buffer
+# );
+#------------------------------------------------------------------------------
+ASM_GLOBAL ASM_PFX(IoWriteFifo8)
+ASM_PFX(IoWriteFifo8):
+ movw 4(%esp), %dx
+ movl 8(%esp), %ecx
+ pushl %esi
+ movl 16(%esp), %esi
+rep outsb
+ popl %esi
+ ret
+
diff --git a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
index 248d522..e02fa04 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
+++ b/OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm
@@ -36,5 +36,27 @@ rep insb
IoReadFifo8 ENDP
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; IoWriteFifo8 (
+; IN UINTN Port,
+; IN UINTN Size,
+; IN VOID *Buffer
+; );
+;------------------------------------------------------------------------------
+IoWriteFifo8 PROC
+
+ mov dx, [esp + 4]
+ mov ecx, [esp + 8]
+ push esi
+ mov esi, [esp + 16]
+rep outsb
+ pop esi
+ ret
+
+IoWriteFifo8 ENDP
+
END
diff --git a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
index 8caab42..c567fc9 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
+++ b/OvmfPkg/Library/QemuFwCfgLib/QemuFwCfgLib.c
@@ -50,6 +50,32 @@ IoReadFifo8 (
OUT VOID *Buffer
);
+/**
+ Writes an 8-bit I/O port fifo from a block of memory.
+
+ Writes the 8-bit I/O fifo port specified by Port.
+
+ The port is written Count times, and the data are obtained
+ from the provided Buffer.
+
+ This function must guarantee that all I/O read and write operations are
+ serialized.
+
+ If 8-bit I/O port operations are not supported, then ASSERT().
+
+ @param Port The I/O port to read.
+ @param Count The number of times to read I/O port.
+ @param Buffer The buffer to store the read data into.
+
+**/
+VOID
+EFIAPI
+IoWriteFifo8 (
+ IN UINTN Port,
+ IN UINTN Count,
+ OUT VOID *Buffer
+ );
+
/**
Returns a boolean indicating if the firmware configuration interface
@@ -132,6 +158,29 @@ QemuFwCfgReadBytes (
}
}
+/**
+ Write firmware configuration bytes from a buffer
+
+ If called multiple times, then the data written will
+ continue at the offset of the firmware configuration
+ item where the previous write ended.
+
+ @param[in] Size - Size in bytes to write
+ @param[in] Buffer - Buffer to read data from
+
+**/
+VOID
+EFIAPI
+QemuFwCfgWriteBytes (
+ IN UINTN Size,
+ IN VOID *Buffer
+ )
+{
+ if (mQemuFwCfgSupported) {
+ IoWriteFifo8 (0x511, Size, Buffer);
+ }
+}
+
/**
Reads a UINT8 firmware configuration value
diff --git a/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.S
b/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.S
index b1125ed..a02323f 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.S
+++ b/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.S
@@ -28,3 +28,20 @@ rep insb
mov %r8, %rdi # restore rdi
ret
+#------------------------------------------------------------------------------
+# VOID
+# EFIAPI
+# IoWriteFifo8 (
+# IN UINTN Port, // rcx
+# IN UINTN Size, // rdx
+# IN VOID *Buffer // r8
+# );
+#------------------------------------------------------------------------------
+ASM_GLOBAL ASM_PFX(IoWriteFifo8)
+ASM_PFX(IoWriteFifo8):
+ xchg %rcx, %rdx
+ xchg %r8, %rsi # rdi: buffer address; r8: save rsi
+rep outsb
+ mov %r8, %rsi # restore rsi
+ ret
+
diff --git a/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.asm
b/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.asm
index c60ad2c..e7af499 100644
--- a/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.asm
+++ b/OvmfPkg/Library/QemuFwCfgLib/X64/IoLibExAsm.asm
@@ -32,5 +32,25 @@ rep insb
IoReadFifo8 ENDP
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; IoWriteFifo8 (
+; IN UINTN Port, // rcx
+; IN UINTN Size, // rdx
+; IN VOID *Buffer // r8
+; );
+;------------------------------------------------------------------------------
+IoWriteFifo8 PROC
+
+ xchg rcx, rdx
+ xchg rsi, r8 ; rdi: buffer address; r8: save rdi
+rep outsb
+ mov rsi, r8 ; restore rdi
+ ret
+
+IoWriteFifo8 ENDP
+
END
--
1.8.0.2
--
dwmw2
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