1 files changed, 22 insertions, 3 deletions

diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index ef773e12af79..bec35f491cb9 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -1585,12 +1585,31 @@ static void piix_ignore_devices_quirk(struct ata_host *host)
                 },
                 { }     /* terminate list */
         };
-        const struct dmi_system_id *dmi = dmi_first_match(ignore_hyperv);
+        static const struct dmi_system_id allow_virtual_pc[] = {
+                {
+                        /* In MS Virtual PC guests the DMI ident is nearly
+                         * identical to a Hyper-V guest. One difference is the
+                         * product version which is used here to identify
+                         * a Virtual PC guest. This entry allows ata_piix to
+                         * drive the emulated hardware.
+                         */
+                        .ident = "MS Virtual PC 2007",
+                        .matches = {
+                                DMI_MATCH(DMI_SYS_VENDOR,
+                                                "Microsoft Corporation"),
+                                DMI_MATCH(DMI_PRODUCT_NAME, "Virtual Machine"),
+                                DMI_MATCH(DMI_PRODUCT_VERSION, "VS2005R2"),
+                        },
+                },
+                { }     /* terminate list */
+        };
+        const struct dmi_system_id *ignore = dmi_first_match(ignore_hyperv);
+        const struct dmi_system_id *allow = dmi_first_match(allow_virtual_pc);
 
-        if (dmi && prefer_ms_hyperv) {
+        if (ignore && !allow && prefer_ms_hyperv) {
                 host->flags |= ATA_HOST_IGNORE_ATA;
                 dev_info(host->dev, "%s detected, ATA device ignore set\n",
-                        dmi->ident);
+                        ignore->ident);
         }
 #endif
 }