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irqchip/gic-v4.1: Add support for VPENDBASER's Dirty+Valid signaling

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When a vPE is made resident, the GIC starts parsing the virtual pending
table to deliver pending interrupts. This takes place asynchronously,
and can at times take a long while. Long enough that the vcpu enters
the guest and hits WFI before any interrupt has been signaled yet.
The vcpu then exits, blocks, and now gets a doorbell. Rince, repeat.

In order to avoid the above, a (optional on GICv4, mandatory on v4.1)
feature allows the GIC to feedback to the hypervisor whether it is
done parsing the VPT by clearing the GICR_VPENDBASER.Dirty bit.
The hypervisor can then wait until the GIC is ready before actually
running the vPE.

Plug the detection code as well as polling on vPE schedule. While
at it, tidy-up the kernel message that displays the GICv4 optional
features.

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier
2020-04-10 11:13:26 +01:00
parent 8f3d9f3542
commit 96806229ca
3 changed files with 28 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/irqchip/irq-gic-v3.c
View File

@@ -873,6 +873,7 @@ static int __gic_update_rdist_properties(struct redist_region *region,
gic_data.rdists.has_rvpeid &= !!(typer & GICR_TYPER_RVPEID);
gic_data.rdists.has_direct_lpi &= (!!(typer & GICR_TYPER_DirectLPIS) |
gic_data.rdists.has_rvpeid);
gic_data.rdists.has_vpend_valid_dirty &= !!(typer & GICR_TYPER_DIRTY);
/* Detect non-sensical configurations */
if (WARN_ON_ONCE(gic_data.rdists.has_rvpeid && !gic_data.rdists.has_vlpis)) {
@@ -893,10 +894,11 @@ static void gic_update_rdist_properties(void)
if (WARN_ON(gic_data.ppi_nr == UINT_MAX))
gic_data.ppi_nr = 0;
pr_info("%d PPIs implemented\n", gic_data.ppi_nr);
pr_info("%sVLPI support, %sdirect LPI support, %sRVPEID support\n",
!gic_data.rdists.has_vlpis ? "no " : "",
!gic_data.rdists.has_direct_lpi ? "no " : "",
!gic_data.rdists.has_rvpeid ? "no " : "");
if (gic_data.rdists.has_vlpis)
pr_info("GICv4 features: %s%s%s\n",
gic_data.rdists.has_direct_lpi ? "DirectLPI " : "",
gic_data.rdists.has_rvpeid ? "RVPEID " : "",
gic_data.rdists.has_vpend_valid_dirty ? "Valid+Dirty " : "");
}
/* Check whether it's single security state view */
@@ -1620,6 +1622,7 @@ static int __init gic_init_bases(void __iomem *dist_base,
gic_data.rdists.has_rvpeid = true;
gic_data.rdists.has_vlpis = true;
gic_data.rdists.has_direct_lpi = true;
gic_data.rdists.has_vpend_valid_dirty = true;
if (WARN_ON(!gic_data.domain) || WARN_ON(!gic_data.rdists.rdist)) {
err = -ENOMEM;