This is a note to let you know that I've just added the patch titled ACPICA: Hardware: Do not flush CPU cache when entering S4 and S5 to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: acpica-hardware-do-not-flush-cpu-cache-when-entering.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 4e0ae6ba3d28624f976b45fa1143f32cf9da6000 Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Date: Wed Dec 22 17:33:51 2021 +0100 ACPICA: Hardware: Do not flush CPU cache when entering S4 and S5 [ Upstream commit 1d4e0b3abb168b2ee1eca99c527cffa1b80b6161 ] ACPICA commit 3dd7e1f3996456ef81bfe14cba29860e8d42949e According to ACPI 6.4, Section 16.2, the CPU cache flushing is required on entering to S1, S2, and S3, but the ACPICA code flushes the CPU cache regardless of the sleep state. Blind cache flush on entering S5 causes problems for TDX. Flushing happens with WBINVD that is not supported in the TDX environment. TDX only supports S5 and adjusting ACPICA code to conform to the spec more strictly fixes the issue. Link: https://github.com/acpica/acpica/commit/3dd7e1f3 Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/acpi/acpica/hwesleep.c b/drivers/acpi/acpica/hwesleep.c index 808fdf54aeebf..7ee2939c08cd4 100644 --- a/drivers/acpi/acpica/hwesleep.c +++ b/drivers/acpi/acpica/hwesleep.c @@ -104,7 +104,9 @@ acpi_status acpi_hw_extended_sleep(u8 sleep_state) /* Flush caches, as per ACPI specification */ - ACPI_FLUSH_CPU_CACHE(); + if (sleep_state < ACPI_STATE_S4) { + ACPI_FLUSH_CPU_CACHE(); + } status = acpi_os_enter_sleep(sleep_state, sleep_control, 0); if (status == AE_CTRL_TERMINATE) { diff --git a/drivers/acpi/acpica/hwsleep.c b/drivers/acpi/acpica/hwsleep.c index 34a3825f25d37..5efa3d8e483e0 100644 --- a/drivers/acpi/acpica/hwsleep.c +++ b/drivers/acpi/acpica/hwsleep.c @@ -110,7 +110,9 @@ acpi_status acpi_hw_legacy_sleep(u8 sleep_state) /* Flush caches, as per ACPI specification */ - ACPI_FLUSH_CPU_CACHE(); + if (sleep_state < ACPI_STATE_S4) { + ACPI_FLUSH_CPU_CACHE(); + } status = acpi_os_enter_sleep(sleep_state, pm1a_control, pm1b_control); if (status == AE_CTRL_TERMINATE) { diff --git a/drivers/acpi/acpica/hwxfsleep.c b/drivers/acpi/acpica/hwxfsleep.c index e4cde23a29061..ba77598ee43e8 100644 --- a/drivers/acpi/acpica/hwxfsleep.c +++ b/drivers/acpi/acpica/hwxfsleep.c @@ -162,8 +162,6 @@ acpi_status acpi_enter_sleep_state_s4bios(void) return_ACPI_STATUS(status); } - ACPI_FLUSH_CPU_CACHE(); - status = acpi_hw_write_port(acpi_gbl_FADT.smi_command, (u32)acpi_gbl_FADT.s4_bios_request, 8); if (ACPI_FAILURE(status)) {