[Qemu-devel] [PATCH v3 1/2] i386: expose floppy-related objects in SSDT

[Roman Kagan]

On x86-based systems Linux determines the presence and the type of
floppy drives via a query of a CMOS field.  So does SeaBIOS when
populating the return data for int 0x13 function 0x08.

Windows doesn't; instead, it requests this information from BIOS via int
0x13/0x08 or through ACPI objects _FDE (Floppy Drive Enumerate) and _FDI
(Floppy Drive Information).  On UEFI systems only ACPI-based detection
is supported.

QEMU used not to provide those objects in its ACPI tables; as a result
floppy drives were invisible to Windows on UEFI/OVMF.

This patch implements those objects in SSDT, populating them via AML
API.  For that, a couple of functions are extern-ified to facilitate
populating those objects in acpi-build.c.

Signed-off-by: Roman Kagan <address@hidden>
Signed-off-by: Denis V. Lunev <address@hidden>
CC: Michael S. Tsirkin <address@hidden>
CC: Igor Mammedov <address@hidden>
CC: Paolo Bonzini <address@hidden>
CC: Richard Henderson <address@hidden>
CC: Eduardo Habkost <address@hidden>
CC: John Snow <address@hidden>
CC: Kevin Wolf <address@hidden>
--
changes since v2:
 - explicit endianness for buffer data
 - reorder code to reduce conflicts with dynamic DSDT patchset

 hw/block/fdc.c         | 11 +++++++
 hw/i386/acpi-build.c   | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/i386/pc.c           | 46 +++++++++++++++++------------
 include/hw/block/fdc.h |  2 ++
 include/hw/i386/pc.h   |  3 ++
 5 files changed, 121 insertions(+), 19 deletions(-)

diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 4292ece..c858c5f 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2408,6 +2408,17 @@ FDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i)
     return isa->state.drives[i].drive;
 }
 
+void isa_fdc_get_drive_geometry(ISADevice *fdc, int i, uint8_t *cylinders,
+                                uint8_t *heads, uint8_t *sectors)
+{
+    FDCtrlISABus *isa = ISA_FDC(fdc);
+    FDrive *drv = &isa->state.drives[i];
+
+    *cylinders = drv->max_track;
+    *heads = (drv->flags & FDISK_DBL_SIDES) ? 2 : 1;
+    *sectors = drv->last_sect;
+}
+
 static const VMStateDescription vmstate_isa_fdc ={
     .name = "fdc",
     .version_id = 2,
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index fa866f6..15e50fb 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -38,6 +38,7 @@
 #include "hw/acpi/bios-linker-loader.h"
 #include "hw/loader.h"
 #include "hw/isa/isa.h"
+#include "hw/block/fdc.h"
 #include "hw/acpi/memory_hotplug.h"
 #include "sysemu/tpm.h"
 #include "hw/acpi/tpm.h"
@@ -105,6 +106,13 @@ typedef struct AcpiPmInfo {
     uint16_t pcihp_io_len;
 } AcpiPmInfo;
 
+typedef struct AcpiFDInfo {
+    uint8_t type;
+    uint8_t cylinders;
+    uint8_t heads;
+    uint8_t sectors;
+} AcpiFDInfo;
+
 typedef struct AcpiMiscInfo {
     bool has_hpet;
     TPMVersion tpm_version;
@@ -112,6 +120,7 @@ typedef struct AcpiMiscInfo {
     unsigned dsdt_size;
     uint16_t pvpanic_port;
     uint16_t applesmc_io_base;
+    AcpiFDInfo fdinfo[2];
 } AcpiMiscInfo;
 
 typedef struct AcpiBuildPciBusHotplugState {
@@ -235,10 +244,25 @@ static void acpi_get_pm_info(AcpiPmInfo *pm)
 
 static void acpi_get_misc_info(AcpiMiscInfo *info)
 {
+    int i;
+    ISADevice *fdc;
+
     info->has_hpet = hpet_find();
     info->tpm_version = tpm_get_version();
     info->pvpanic_port = pvpanic_port();
     info->applesmc_io_base = applesmc_port();
+
+    fdc = pc_find_fdc0();
+    if (fdc) {
+        for (i = 0; i < ARRAY_SIZE(info->fdinfo); i++) {
+            AcpiFDInfo *fdinfo = &info->fdinfo[i];
+            fdinfo->type = isa_fdc_get_drive_type(fdc, i);
+            if (fdinfo->type < FDRIVE_DRV_NONE) {
+                isa_fdc_get_drive_geometry(fdc, i, &fdinfo->cylinders,
+                                           &fdinfo->heads, &fdinfo->sectors);
+            }
+        }
+    }
 }
 
 /*
@@ -900,6 +924,40 @@ static Aml *build_crs(PCIHostState *host,
     return crs;
 }
 
+static Aml *build_fdinfo_aml(int idx, AcpiFDInfo *fdinfo)
+{
+    Aml *dev, *fdi;
+
+    dev = aml_device("FLP%c", 'A' + idx);
+
+    aml_append(dev, aml_name_decl("_ADR", aml_int(idx)));
+
+    fdi = aml_package(0x10);
+    aml_append(fdi, aml_int(idx));  /* Drive Number */
+    aml_append(fdi,
+        aml_int(cmos_get_fd_drive_type(fdinfo->type)));  /* Device Type */
+    aml_append(fdi,
+        aml_int(fdinfo->cylinders - 1));  /* Maximum Cylinder Number */
+    aml_append(fdi, aml_int(fdinfo->sectors));  /* Maximum Sector Number */
+    aml_append(fdi, aml_int(fdinfo->heads - 1));  /* Maximum Head Number */
+    /* SeaBIOS returns the below values for int 0x13 func 0x08 regardless of
+     * the drive type, so shall we */
+    aml_append(fdi, aml_int(0xAF));  /* disk_specify_1 */
+    aml_append(fdi, aml_int(0x02));  /* disk_specify_2 */
+    aml_append(fdi, aml_int(0x25));  /* disk_motor_wait */
+    aml_append(fdi, aml_int(0x02));  /* disk_sector_siz */
+    aml_append(fdi, aml_int(0x12));  /* disk_eot */
+    aml_append(fdi, aml_int(0x1B));  /* disk_rw_gap */
+    aml_append(fdi, aml_int(0xFF));  /* disk_dtl */
+    aml_append(fdi, aml_int(0x6C));  /* disk_formt_gap */
+    aml_append(fdi, aml_int(0xF6));  /* disk_fill */
+    aml_append(fdi, aml_int(0x0F));  /* disk_head_sttl */
+    aml_append(fdi, aml_int(0x08));  /* disk_motor_strt */
+
+    aml_append(dev, aml_name_decl("_FDI", fdi));
+    return dev;
+}
+
 static void
 build_ssdt(GArray *table_data, GArray *linker,
            AcpiCpuInfo *cpu, AcpiPmInfo *pm, AcpiMiscInfo *misc,
@@ -1071,6 +1129,26 @@ build_ssdt(GArray *table_data, GArray *linker,
     aml_append(scope, aml_name_decl("_S5", pkg));
     aml_append(ssdt, scope);
 
+    {
+        uint32_t fde_buf[5] = {0, 0, 0, 0, cpu_to_le32(0x2)};
+
+        scope = aml_scope("\\_SB.PCI0.ISA.FDC0");
+
+        for (i = 0; i < ARRAY_SIZE(misc->fdinfo); i++) {
+            AcpiFDInfo *fdinfo = &misc->fdinfo[i];
+            if (fdinfo->type != FDRIVE_DRV_NONE) {
+                fde_buf[i] = cpu_to_le32(0x1);
+                aml_append(scope, build_fdinfo_aml(i, fdinfo));
+            }
+        }
+
+        aml_append(scope,
+            aml_name_decl("_FDE",
+                aml_buffer(sizeof(fde_buf), (uint8_t *) fde_buf)));
+
+        aml_append(ssdt, scope);
+    }
+
     if (misc->applesmc_io_base) {
         scope = aml_scope("\\_SB.PCI0.ISA");
         dev = aml_device("SMC");
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 426424a..c68e55c 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -208,7 +208,7 @@ static void pic_irq_request(void *opaque, int irq, int 
level)
 
 #define REG_EQUIPMENT_BYTE          0x14
 
-static int cmos_get_fd_drive_type(FDriveType fd0)
+int cmos_get_fd_drive_type(FDriveType fd0)
 {
     int val;
 
@@ -369,6 +369,31 @@ static const char * const fdc_container_path[] = {
     "/unattached", "/peripheral", "/peripheral-anon"
 };
 
+/*
+ * Locate the FDC at IO address 0x3f0, in order to configure the CMOS registers
+ * and ACPI objects.
+ */
+ISADevice *pc_find_fdc0(void)
+{
+    int i;
+    Object *container;
+    CheckFdcState state = { 0 };
+
+    for (i = 0; i < ARRAY_SIZE(fdc_container_path); i++) {
+        container = container_get(qdev_get_machine(), fdc_container_path[i]);
+        object_child_foreach(container, check_fdc, &state);
+    }
+
+    if (state.multiple) {
+        error_report("warning: multiple floppy disk controllers with "
+                     "iobase=0x3f0 have been found;\n"
+                     "the one being picked for CMOS setup might not reflect "
+                     "your intent");
+    }
+
+    return state.floppy;
+}
+
 static void pc_cmos_init_late(void *opaque)
 {
     pc_cmos_init_late_arg *arg = opaque;
@@ -377,8 +402,6 @@ static void pc_cmos_init_late(void *opaque)
     int8_t heads, sectors;
     int val;
     int i, trans;
-    Object *container;
-    CheckFdcState state = { 0 };
 
     val = 0;
     if (ide_get_geometry(arg->idebus[0], 0,
@@ -408,22 +431,7 @@ static void pc_cmos_init_late(void *opaque)
     }
     rtc_set_memory(s, 0x39, val);
 
-    /*
-     * Locate the FDC at IO address 0x3f0, and configure the CMOS registers
-     * accordingly.
-     */
-    for (i = 0; i < ARRAY_SIZE(fdc_container_path); i++) {
-        container = container_get(qdev_get_machine(), fdc_container_path[i]);
-        object_child_foreach(container, check_fdc, &state);
-    }
-
-    if (state.multiple) {
-        error_report("warning: multiple floppy disk controllers with "
-                     "iobase=0x3f0 have been found;\n"
-                     "the one being picked for CMOS setup might not reflect "
-                     "your intent");
-    }
-    pc_cmos_init_floppy(s, state.floppy);
+    pc_cmos_init_floppy(s, pc_find_fdc0());
 
     qemu_unregister_reset(pc_cmos_init_late, opaque);
 }
diff --git a/include/hw/block/fdc.h b/include/hw/block/fdc.h
index d48b2f8..adaf3dc 100644
--- a/include/hw/block/fdc.h
+++ b/include/hw/block/fdc.h
@@ -22,5 +22,7 @@ void sun4m_fdctrl_init(qemu_irq irq, hwaddr io_base,
                        DriveInfo **fds, qemu_irq *fdc_tc);
 
 FDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i);
+void isa_fdc_get_drive_geometry(ISADevice *fdc, int i, uint8_t *cylinders,
+                                uint8_t *heads, uint8_t *sectors);
 
 #endif
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 4bf4faf..6948e63 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -224,6 +224,9 @@ typedef void (*cpu_set_smm_t)(int smm, void *arg);
 
 void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name);
 
+ISADevice *pc_find_fdc0(void);
+int cmos_get_fd_drive_type(FDriveType fd0);
+
 /* acpi_piix.c */
 
 I2CBus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
-- 
2.5.0