6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nianyao Tang <tangnianyao@xxxxxxxxxx>
commit 80e9963fb3b5509dfcabe9652d56bf4b35542055 upstream.
As per the GICv4.1 spec (Arm IHI 0069H, 5.3.19):
"A VMAPP with {V, Alloc}=={0, x} is self-synchronizing, This means the ITS
command queue does not show the command as consumed until all of its
effects are completed."
Furthermore, VSYNC is allowed to deliver an SError when referencing a
non existent VPE.
By these definitions, a VMAPP followed by a VSYNC is a bug, as the
later references a VPE that has been unmapped by the former.
Fix it by eliding the VSYNC in this scenario.
Fixes: 64edfaa9a234 ("irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP")
Signed-off-by: Nianyao Tang <tangnianyao@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240406022737.3898763-1-tangnianyao@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -786,6 +786,7 @@ static struct its_vpe *its_build_vmapp_c
struct its_cmd_block *cmd,
struct its_cmd_desc *desc)
{
+ struct its_vpe *vpe = valid_vpe(its, desc->its_vmapp_cmd.vpe);
unsigned long vpt_addr, vconf_addr;
u64 target;
bool alloc;
@@ -798,6 +799,11 @@ static struct its_vpe *its_build_vmapp_c
if (is_v4_1(its)) {
alloc = !atomic_dec_return(&desc->its_vmapp_cmd.vpe->vmapp_count);
its_encode_alloc(cmd, alloc);
+ /*
+ * Unmapping a VPE is self-synchronizing on GICv4.1,
+ * no need to issue a VSYNC.
+ */
+ vpe = NULL;
}
goto out;
@@ -832,7 +838,7 @@ static struct its_vpe *its_build_vmapp_c
out:
its_fixup_cmd(cmd);
- return valid_vpe(its, desc->its_vmapp_cmd.vpe);
+ return vpe;
}
static struct its_vpe *its_build_vmapti_cmd(struct its_node *its,
