[seabios PATCH for qemu 2.10 0/2] seabios: build ACPI 1.0-compatible ACPI tables

[Paolo Bonzini]

Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but
new operating systems would like to have rev3 (ACPI 2.0).
Since old operating systems do not know about XSDTs, the
solution is to point the RSDT to a v1 FADT and the XSDT to a
rev3 FADT.

Paolo Bonzini (2):
  seabios: build RSDT from XSDT
  seabios: create rev1 FADT in compatibility RSDT

src/fw/paravirt.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/std/acpi.h    | 11 +++++++++
 2 files changed, 78 insertions(+), 1 deletion(-)

[seabios PATCH 1/2] seabios: build RSDT from XSDT

[Paolo Bonzini]

Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but
new operating systems would like to have rev3 (ACPI 2.0).

Since old operating systems do not know about XSDTs, the
solution is to point the RSDT to a rev1 FADT and the XSDT to a
rev3 FADT.

But, edk2 is not able to handle QEMU providing two FADTs and barfs when
it sees the second; edk2 subscribes to the view that the platform code
(meaning not only OVMF, but transitively QEMU's ACPI table builder)
should not handle such hacks; it's common edk2 code that should handle
FADT rev1 vs. rev3 and RSDT vs. XSDT.

These patches make SeaBIOS follow the same model as edk2, the only
difference being how the two identify ACPI tables from the BIOS
linker/loader script.  For SeaBIOS, this task is actually much
simpler since it can just look into the RSDP: if QEMU only
provides an XSDT, SeaBIOS takes care of building the RSDT and
rev1 FADT to satisfy ACPI 1.0-compliant operating systems.

This part makes SeaBIOS build an RSDT out of an existing XSDT,
patching the RSDP to point to the RSDT.

Reviewed-by: Phil Dennis-Jordan 
Signed-off-by: Paolo Bonzini 
---
 src/fw/paravirt.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 src/std/acpi.h    | 11 +++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index 5b23d78..927fd75 100644
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -25,6 +25,7 @@
 #include "x86.h" // cpuid
 #include "xen.h" // xen_biostable_setup
 #include "stacks.h" // yield
+#include "std/acpi.h"

// Amount of continuous ram under 4Gig
 u32 RamSize;
@@ -147,6 +148,50 @@ static void msr_feature_control_setup(void)
         wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits);
 }

+static void
+build_compatibility_rsdt(void)
+{
+    if (RsdpAddr->rsdt_physical_address)
+        return;
+
+    u64 xsdt_addr = RsdpAddr->xsdt_physical_address;
+    if (xsdt_addr & ~0xffffffffULL)
+        return;
+
+    struct xsdt_descriptor_rev1 *xsdt = (void*)(u32)xsdt_addr;
+    void *end = (void*)xsdt + xsdt->length;
+    struct rsdt_descriptor_rev1 *rsdt;
+    int rsdt_size = offsetof(struct rsdt_descriptor_rev1, table_offset_entry[0]);
+    int i;
+    for (i=0; (void*)&xsdt->table_offset_entry[i] < end; i++) {
+        u64 tbl_addr = xsdt->table_offset_entry[i];
+        if (!tbl_addr || (tbl_addr & ~0xffffffffULL))
+            continue;
+        rsdt_size += 4;
+    }
+
+    rsdt = malloc_high(rsdt_size);
+    RsdpAddr->rsdt_physical_address = (u32)rsdt;
+    RsdpAddr->checksum -= checksum(RsdpAddr,
+				   offsetof(struct rsdp_descriptor, length));
+    RsdpAddr->extended_checksum -= checksum(RsdpAddr,
+					    sizeof(struct rsdp_descriptor));
+
+    memcpy(rsdt, xsdt, sizeof(struct acpi_table_header));
+    rsdt->signature = RSDT_SIGNATURE;
+    rsdt->length = rsdt_size;
+    rsdt->revision = 1;
+    int j;
+    for (i=j=0; (void*)&xsdt->table_offset_entry[i] < end; i++) {
+        u64 tbl_addr = xsdt->table_offset_entry[i];
+        if (!tbl_addr || (tbl_addr & ~0xffffffffULL))
+            continue;
+        rsdt->table_offset_entry[j++] = (u32)tbl_addr;
+    }
+
+    rsdt->checksum -= checksum(rsdt, rsdt_size);
+}
+
 void
 qemu_platform_setup(void)
 {
@@ -186,8 +231,10 @@ qemu_platform_setup(void)

RsdpAddr = find_acpi_rsdp();

-        if (RsdpAddr)
+        if (RsdpAddr) {
+            build_compatibility_rsdt();
             return;
+        }

/* If present, loader should have installed an RSDP.
          * Not installed? We might still be able to continue
diff --git a/src/std/acpi.h b/src/std/acpi.h
index c2ea707..a77b53c 100644
--- a/src/std/acpi.h
+++ b/src/std/acpi.h
@@ -133,6 +133,17 @@ struct rsdt_descriptor_rev1
 } PACKED;

/*
+ * ACPI 2.0 Extended System Description Table (XSDT)
+ */
+#define XSDT_SIGNATURE 0x54445358 // XSDT
+struct xsdt_descriptor_rev1
+{
+    ACPI_TABLE_HEADER_DEF       /* ACPI common table header */
+    u64 table_offset_entry[0];  /* Array of pointers to other */
+    /* ACPI tables */
+} PACKED;
+
+/*
  * ACPI 1.0 Firmware ACPI Control Structure (FACS)
  */
 #define FACS_SIGNATURE 0x53434146 // FACS

[seabios PATCH 2/2] seabios: create rev1 FADT in compatibility RSDT

[Paolo Bonzini]

This patch completes the job, presenting a rev1 FADT inside the
compatibility RSDT, so that ACPI 1.0 operating systems such as
Windows 2000 are not broken.

Signed-off-by: Paolo Bonzini 
---
 src/fw/paravirt.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index 927fd75..97e2fe3 100644
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -148,6 +148,20 @@ static void msr_feature_control_setup(void)
         wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits);
 }

+static void*
+build_rev1_fadt(struct fadt_descriptor_rev1 *fadt_v3)
+{
+    struct fadt_descriptor_rev1 *fadt_v1 = malloc_high(sizeof *fadt_v1);
+
+    memcpy(fadt_v1, fadt_v3, sizeof *fadt_v1);
+    fadt_v1->length = sizeof *fadt_v1;
+    fadt_v1->revision = 1;
+    // the upper 23 bits are reserved in the rev1 FADT
+    fadt_v1->flags &= 0x1ff;
+    fadt_v1->checksum -= checksum(fadt_v1, fadt_v1->length);
+    return fadt_v1;
+}
+
 static void
 build_compatibility_rsdt(void)
 {
@@ -186,6 +200,11 @@ build_compatibility_rsdt(void)
         u64 tbl_addr = xsdt->table_offset_entry[i];
         if (!tbl_addr || (tbl_addr & ~0xffffffffULL))
             continue;
+        struct acpi_table_header *tbl = (void*)(u32)tbl_addr;
+        // for compatibility with Windows 2000, the RSDT should contain
+        // an ACPI 1.0 FADT (table revision 1)
+        if (tbl->signature == FACP_SIGNATURE && tbl->revision > 1)
+            tbl_addr = (u32)build_rev1_fadt((void *)tbl);
         rsdt->table_offset_entry[j++] = (u32)tbl_addr;
     }

[seabios PATCH 1/2] seabios: build RSDT from XSDT

[Michael S. Tsirkin]

On Wed, Jul 26, 2017 at 11:42:34AM +0200, Paolo Bonzini wrote:
> Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but
> new operating systems would like to have rev3 (ACPI 2.0).
>
> Since old operating systems do not know about XSDTs, the
> solution is to point the RSDT to a rev1 FADT and the XSDT to a
> rev3 FADT.
>
> But, edk2 is not able to handle QEMU providing two FADTs and barfs when
> it sees the second; edk2 subscribes to the view that the platform code
> (meaning not only OVMF, but transitively QEMU's ACPI table builder)
> should not handle such hacks; it's common edk2 code that should handle
> FADT rev1 vs. rev3 and RSDT vs. XSDT.

What exactly does it do wrt RSDT?
> These patches make SeaBIOS follow the same model as edk2, the only
> difference being how the two identify ACPI tables from the BIOS
> linker/loader script.  For SeaBIOS, this task is actually much
> simpler since it can just look into the RSDP: if QEMU only
> provides an XSDT, SeaBIOS takes care of building the RSDT and
> rev1 FADT to satisfy ACPI 1.0-compliant operating systems.
>
> This part makes SeaBIOS build an RSDT out of an existing XSDT,
> patching the RSDP to point to the RSDT.
>
> Reviewed-by: Phil Dennis-Jordan 
> Signed-off-by: Paolo Bonzini
>
> src/fw/paravirt.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  src/std/acpi.h    | 11 +++++++++++
>  2 files changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
> index 5b23d78..927fd75 100644
> --- a/src/fw/paravirt.c
> +++ b/src/fw/paravirt.c
> @@ -25,6 +25,7 @@
>  #include "x86.h" // cpuid
>  #include "xen.h" // xen_biostable_setup
>  #include "stacks.h" // yield
> +#include "std/acpi.h"
>
> // Amount of continuous ram under 4Gig
>  u32 RamSize;
> @@ -147,6 +148,50 @@ static void msr_feature_control_setup(void)
>          wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits);
>  }
>
> +static void
> +build_compatibility_rsdt(void)
> +{
> if (RsdpAddr->rsdt_physical_address)
>    return;
> u64 xsdt_addr = RsdpAddr->xsdt_physical_address;
> if (xsdt_addr & ~0xffffffffULL)
>    return;
> struct xsdt_descriptor_rev1 *xsdt = (void*)(u32)xsdt_addr;
> void *end = (void*)xsdt + xsdt->length;
> struct rsdt_descriptor_rev1 *rsdt;
> int rsdt_size = offsetof(struct rsdt_descriptor_rev1, table_offset_entry[0]);
> int i;
> for (i=0; (void*)&xsdt->table_offset_entry[i] < end; i++) {
>    u64 tbl_addr = xsdt->table_offset_entry[i];
>    if (!tbl_addr || (tbl_addr & ~0xffffffffULL))
>        continue;
>    rsdt_size += 4;
> }
> rsdt = malloc_high(rsdt_size);
> RsdpAddr->rsdt_physical_address = (u32)rsdt;
> RsdpAddr->checksum -= checksum(RsdpAddr,
> 		   offsetof(struct rsdp_descriptor, length));
> RsdpAddr->extended_checksum -= checksum(RsdpAddr,
> 			    sizeof(struct rsdp_descriptor));
> memcpy(rsdt, xsdt, sizeof(struct acpi_table_header));
> rsdt->signature = RSDT_SIGNATURE;
> rsdt->length = rsdt_size;
> rsdt->revision = 1;
> int j;
> for (i=j=0; (void*)&xsdt->table_offset_entry[i] < end; i++) {
>    u64 tbl_addr = xsdt->table_offset_entry[i];
>    if (!tbl_addr || (tbl_addr & ~0xffffffffULL))
>        continue;
>    rsdt->table_offset_entry[j++] = (u32)tbl_addr;
> }
> rsdt->checksum -= checksum(rsdt, rsdt_size);
>
> +}
>
> void
>  qemu_platform_setup(void)
>  {
> @@ -186,8 +231,10 @@ qemu_platform_setup(void)
>      RsdpAddr = find_acpi_rsdp();
>
>    if (RsdpAddr)
>    if (RsdpAddr) {
>        build_compatibility_rsdt();
>        return;
>    }
>
>    /* If present, loader should have installed an RSDP.
>     * Not installed? We might still be able to continue
>
> diff --git a/src/std/acpi.h b/src/std/acpi.h
> index c2ea707..a77b53c 100644
> --- a/src/std/acpi.h
> +++ b/src/std/acpi.h
> @@ -133,6 +133,17 @@ struct rsdt_descriptor_rev1
>  } PACKED;
>
> /*
> ACPI 2.0 Extended System Description Table (XSDT)
> */
>
> +#define XSDT_SIGNATURE 0x54445358 // XSDT
> +struct xsdt_descriptor_rev1
> +{
> ACPI_TABLE_HEADER_DEF       /* ACPI common table header */
> u64 table_offset_entry[0];  /* Array of pointers to other */
> /* ACPI tables */
>
> +} PACKED;
>
> +/*
> ACPI 1.0 Firmware ACPI Control Structure (FACS)
>
> */
> #define FACS_SIGNATURE 0x53434146 // FACS
>
> 2.13.3

[seabios PATCH 1/2] seabios: build RSDT from XSDT

[Paolo Bonzini]

----- Original Message -----
> From: "Michael S. Tsirkin" 
> To: "Paolo Bonzini" 
> Cc: [e-mail], "Kevin O'Connor" , [e-mail], [e-mail],
> [e-mail], [e-mail], [e-mail], [e-mail], [e-mail]
> Sent: Wednesday, July 26, 2017 10:05:03 PM
> Subject: Re: [seabios PATCH 1/2] seabios: build RSDT from XSDT
>
> On Wed, Jul 26, 2017 at 11:42:34AM +0200, Paolo Bonzini wrote:
> > Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but
> > new operating systems would like to have rev3 (ACPI 2.0).
> >
> > Since old operating systems do not know about XSDTs, the
> > solution is to point the RSDT to a rev1 FADT and the XSDT to a
> > rev3 FADT.
> >
> > But, edk2 is not able to handle QEMU providing two FADTs and barfs when
> > it sees the second; edk2 subscribes to the view that the platform code
> > (meaning not only OVMF, but transitively QEMU's ACPI table builder)
> > should not handle such hacks; it's common edk2 code that should handle
> > FADT rev1 vs. rev3 and RSDT vs. XSDT.
>
> What exactly does it do wrt RSDT?

It ignores the one produced by QEMU and builds it from scratch.  Same
for RSDP and XSDT.

Paolo

[Michael S. Tsirkin]

On Wed, Jul 26, 2017 at 11:42:33AM +0200, Paolo Bonzini wrote:
> Old operating systems would like to have a rev1 (ACPI 1.0) FADT, but
> new operating systems would like to have rev3 (ACPI 2.0).
> Since old operating systems do not know about XSDTs, the
> solution is to point the RSDT to a v1 FADT and the XSDT to a
> rev3 FADT.

So I think for 2.10 Igor's patch is much smaller and only
touches QEMU, I'm inclined to merge just that one.
Let's discuss this after 2.10 is out.
> Paolo Bonzini (2):
>   seabios: build RSDT from XSDT
>   seabios: create rev1 FADT in compatibility RSDT
>
> src/fw/paravirt.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  src/std/acpi.h    | 11 +++++++++
>  2 files changed, 78 insertions(+), 1 deletion(-)