KVM guest has two levels of address translation: guest tlb translates
GVA to GPA, and root tlb translates GPA to HPA. By default guest's CCA
is controlled by guest tlb, but Loongson-3 maintains all cache coherency
by hardware (including multi-core coherency and I/O DMA coherency) so it
prefers all guest mappings be cacheable mappings. Thus, we use root tlb
to control guest's CCA for Loongson-3.
Signed-off-by: Huacai Chen <che...@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.y...@flygoat.com>
---
arch/mips/kvm/vz.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
index 422cd06..e30ebb2 100644
--- a/arch/mips/kvm/vz.c
+++ b/arch/mips/kvm/vz.c
@@ -2871,6 +2871,10 @@ static int kvm_vz_hardware_enable(void)
if (cpu_has_guestctl2)
clear_c0_guestctl2(0x3f << 10);
+ /* Control guest CCA attribute */
+ if (cpu_has_csr())
+ csr_writel(csr_readl(0xffffffec) | 0x1, 0xffffffec);
+
return 0;
}
--
2.7.0
