[xen stable-4.18] xen/x86/pvh: handle ACPI RSDT table in PVH Dom0 build

[patchbot@xxxxxxx]

commit b7e54ae8389dad2f0582d32edb667f6bdbf9df37
Author:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
AuthorDate: Tue Sep 24 15:00:29 2024 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 24 15:00:29 2024 +0200

    xen/x86/pvh: handle ACPI RSDT table in PVH Dom0 build
    
    Xen always generates an XSDT table even if the firmware only provided an
    RSDT table.  Copy the RSDT header from the firmware table, adjusting the
    signature, for the XSDT table when not provided by the firmware.
    
    This is necessary to run Xen on QEMU.
    
    Fixes: 1d74282c455f ('x86: setup PVHv2 Dom0 ACPI tables')
    Suggested-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
    Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    master commit: 6e7f7a0c16c4d406bda6d4a900252ff63a7c5fad
    master date: 2024-09-12 09:18:25 +0200
---
 xen/arch/x86/hvm/dom0_build.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index c7d47d0d4c..411beb3f06 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -960,7 +960,16 @@ static int __init pvh_setup_acpi_xsdt(struct domain *d, 
paddr_t madt_addr,
         rc = -EINVAL;
         goto out;
     }
-    xsdt_paddr = rsdp->xsdt_physical_address;
+    /*
+     * Note the header is the same for both RSDT and XSDT, so it's fine to
+     * copy the native RSDT header to the Xen crafted XSDT if no native
+     * XSDT is available.
+     */
+    if ( rsdp->revision > 1 && rsdp->xsdt_physical_address )
+        xsdt_paddr = rsdp->xsdt_physical_address;
+    else
+        xsdt_paddr = rsdp->rsdt_physical_address;
+
     acpi_os_unmap_memory(rsdp, sizeof(*rsdp));
     table = acpi_os_map_memory(xsdt_paddr, sizeof(*table));
     if ( !table )
@@ -972,6 +981,12 @@ static int __init pvh_setup_acpi_xsdt(struct domain *d, 
paddr_t madt_addr,
     xsdt->header = *table;
     acpi_os_unmap_memory(table, sizeof(*table));
 
+    /*
+     * In case the header is an RSDT copy, unconditionally ensure it has
+     * an XSDT sig.
+     */
+    xsdt->header.signature[0] = 'X';
+
     /* Add the custom MADT. */
     xsdt->table_offset_entry[0] = madt_addr;
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.18