add vmware support, debug logging to serial port, and fix ps2 routine clobbering registers

1 files changed, 174 insertions, 0 deletions

diff --git a/vmware.h b/vmware.h
new file mode 100644
index 0000000..8cb8f0f
--- /dev/null
+++ b/vmware.h
@@ -0,0 +1,174 @@
+/*
+ * VBMouse - VMware communication routines
+ * Copyright (C) 2022 Javier S. Pedro
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef VMWARE_H
+#define VMWARE_H
+
+#include <stdint.h>
+
+/* Ideas from https://wiki.osdev.org/VMware_tools */
+
+#define VMWARE_MAGIC 0x564D5868UL
+#define VMWARE_PORT  0x5658
+
+enum vmware_cmds {
+	VMWARE_CMD_GETVERSION          = 10,
+	VMWARE_CMD_ABSPOINTER_DATA     = 39,
+	VMWARE_CMD_ABSPOINTER_STATUS   = 40,
+	VMWARE_CMD_ABSPOINTER_COMMAND  = 41
+};
+
+enum vmware_abspointer_cmds {
+	VMWARE_ABSPOINTER_CMD_ENABLE           = 0x45414552UL,
+	VMWARE_ABSPOINTER_CMD_DISABLE          = 0x000000f5UL,
+	VMWARE_ABSPOINTER_CMD_REQUEST_RELATIVE = 0x4c455252UL,
+	VMWARE_ABSPOINTER_CMD_REQUEST_ABSOLUTE = 0x53424152UL,
+};
+
+enum vmware_abspointer_status {
+	VMWARE_ABSPOINTER_STATUS_MASK_ERROR    = 0xFFFF0000UL,
+	VMWARE_ABSPOINTER_STATUS_MASK_DATA     = 0x0000FFFFUL
+};
+
+enum vmware_abspointer_data_status {
+	VMWARE_ABSPOINTER_STATUS_RELATIVE      = 0x00010000U,
+	VMWARE_ABSPOINTER_STATUS_BUTTON_LEFT   = 0x20,
+	VMWARE_ABSPOINTER_STATUS_BUTTON_RIGHT  = 0x10,
+	VMWARE_ABSPOINTER_STATUS_BUTTON_MIDDLE = 0x08,
+};
+
+struct vmware_call_regs {
+	union {
+		uint32_t eax;
+		uint32_t magic;
+	};
+	union {
+		uint32_t ebx;
+		uint32_t size;
+	};
+	union {
+		uint32_t ecx;
+		uint32_t command;
+	};
+	union {
+		uint32_t edx;
+		uint32_t port;
+	};
+};
+
+struct vmware_abspointer_data {
+	uint32_t status;
+	int32_t x;
+	int32_t y;
+	int32_t z;
+};
+
+#define VMWARE_ABSPOINTER_DATA_PACKET_SIZE 4
+
+static inline void vmware_call(struct vmware_call_regs __far * regs);
+#pragma aux vmware_call = \
+	"pushad" /* First make a copy of all 32-bit registers, to avoid clobbering them. */ \
+	"mov eax, es:[di + 4*0]" \
+	"mov ebx, es:[di + 4*1]" \
+	"mov ecx, es:[di + 4*2]" \
+	"mov edx, es:[di + 4*3]" \
+	"in eax, dx"  /* This performs the actual backdoor call. */ \
+	"mov es:[di + 4*0], eax" \
+	"mov es:[di + 4*1], ebx" \
+	"mov es:[di + 4*2], ecx" \
+	"mov es:[di + 4*3], edx" \
+	"popad" \
+	__parm [es di] \
+	__modify []
+
+/** Checks the presence of the VMware backdoor by comparing magic numbers.
+ *  @return detected version of the vmware protocol (0-6), -1 if not detected. */
+static int32_t vmware_get_version(void)
+{
+	struct vmware_call_regs regs;
+	regs.magic = VMWARE_MAGIC;
+	regs.port = VMWARE_PORT;
+	regs.command = VMWARE_CMD_GETVERSION;
+	regs.ebx = ~VMWARE_MAGIC;
+	vmware_call(&regs);
+	if (regs.ebx != VMWARE_MAGIC) {
+		return -1;
+	}
+	return regs.eax;
+}
+
+/** Sends a command to the VMware absolute pointing interface.
+ *  @param cmd see VMWARE_ABSPOINTER_CMD_*. */
+static void vmware_abspointer_cmd(uint32_t cmd)
+{
+	struct vmware_call_regs regs;
+	regs.magic = VMWARE_MAGIC;
+	regs.port = VMWARE_PORT;
+	regs.command = VMWARE_CMD_ABSPOINTER_COMMAND;
+	regs.ebx = cmd;
+	vmware_call(&regs);
+}
+
+/** Gets the status reg from the VMware absolute pointing interface.
+ *  @return status
+ *     VMWARE_ABSPOINTER_STATUS_MASK_ERROR bits: error flags.
+ *     VMWARE_ABSPOINTER_STATUS_MASK_DATA bits: amount of data available to read. */
+static uint32_t vmware_abspointer_status(void)
+{
+	struct vmware_call_regs regs;
+	regs.magic = VMWARE_MAGIC;
+	regs.port = VMWARE_PORT;
+	regs.command = VMWARE_CMD_ABSPOINTER_STATUS;
+	regs.ebx = 0;
+	vmware_call(&regs);
+	return regs.eax;
+}
+
+/** Reads data from the VMware absolute pointing interface.
+ *  @param size amount of data to read (value between 1 and 4)
+ *    ensure it is less than the amount of data available,
+ *    qemu disconnects us if we read more than we can.
+ *  @return status
+ *     VMWARE_ABSPOINTER_STATUS_MASK_ERROR bits: error flags.
+ *     VMWARE_ABSPOINTER_STATUS_MASK_DATA bits: amount of data available to read. */
+static void vmware_abspointer_data(unsigned size, struct vmware_abspointer_data __far * data)
+{
+	union u {
+		struct vmware_call_regs regs;
+		struct vmware_abspointer_data data;
+	} __far *p = (union u __far *) data;
+	p->regs.magic = VMWARE_MAGIC;
+	p->regs.port = VMWARE_PORT;
+	p->regs.command = VMWARE_CMD_ABSPOINTER_DATA;
+	p->regs.size = size;
+	vmware_call(&p->regs);
+}
+
+/** Reads (and discards) all available data in the VMware absolute pointing interface. */
+static void vmware_abspointer_data_clear(void)
+{
+	uint16_t data_avail;
+	// Drop any data in the queue
+	while ((data_avail = vmware_abspointer_status())) {
+		struct vmware_abspointer_data data;
+		vmware_abspointer_data(MIN(4, data_avail), &data);
+	}
+}
+
+#endif // VMWARE_H