You are probably hitting one of LP#1715700 and LP#1714331. (Upgrading from "Zesty" (17.04) to "Artful" (17.10) seems to imply a QEMU upgrade from 2.8 to 2.10.)
LP#1715700 was fixed in edk2 commit range b68c793144e8..947f3737abf6:
ba1d245f1d3d OvmfPkg/CsmSupportLib: move PAM register addresses to IndustryStandard
ce461ae240a7 OvmfPkg/QemuVideoDxe/VbeShim: rename Status to Segment0AllocationStatus
947f3737abf6 OvmfPkg/QemuVideoDxe/VbeShim: handle PAM1 register on Q35 correctly
edk2 commits related to LP#1714331 are:
198a46d768fb MdeModulePkg/AcpiTableDxe: improve FADT.{DSDT,X_DSDT} mutual exclusion
78807f605082 MdeModulePkg/AcpiTableDxe: Not make FADT.{DSDT,X_DSDT} mutual exclusion
072060a6f81b OvmfPkg: Allow multiple add-pointer linker commands to same ACPI table
at least; in this order.
Regarding the change to the boot animation, that's due to commit 6e5e544f227f ("OvmfPkg: Install BGRT ACPI table", 2017-01-06).
You are probably hitting one of LP#1715700 and LP#1714331. (Upgrading from "Zesty" (17.04) to "Artful" (17.10) seems to imply a QEMU upgrade from 2.8 to 2.10.)
LP#1715700 was fixed in edk2 commit range b68c793144e8. .947f3737abf6:
ba1d245f1d3d OvmfPkg/ CsmSupportLib: move PAM register addresses to IndustryStandard QemuVideoDxe/ VbeShim: rename Status to Segment0Allocat ionStatus QemuVideoDxe/ VbeShim: handle PAM1 register on Q35 correctly
ce461ae240a7 OvmfPkg/
947f3737abf6 OvmfPkg/
edk2 commits related to LP#1714331 are:
198a46d768fb MdeModulePkg/ AcpiTableDxe: improve FADT.{DSDT,X_DSDT} mutual exclusion AcpiTableDxe: Not make FADT.{DSDT,X_DSDT} mutual exclusion
78807f605082 MdeModulePkg/
072060a6f81b OvmfPkg: Allow multiple add-pointer linker commands to same ACPI table
at least; in this order.
Regarding the change to the boot animation, that's due to commit 6e5e544f227f ("OvmfPkg: Install BGRT ACPI table", 2017-01-06).