[PATCH V2 07/14] KVM: MIPS: Use root tlb to control guest's CCA for Loongson-3

Huacai Chen
2020-04-24T11:11:07Z

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 <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
arch/mips/kvm/vz.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
index 422cd06..f9fbbc16 100644
--- a/arch/mips/kvm/vz.c
+++ b/arch/mips/kvm/vz.c
@@ -2871,6 +2871,12 @@ static int kvm_vz_hardware_enable(void)
if (cpu_has_guestctl2)
clear_c0_guestctl2(0x3f << 10);

+#ifdef CONFIG_CPU_LOONGSON64
+ /* Control guest CCA attribute */
+ if (cpu_has_csr())
+ csr_writel(csr_readl(0xffffffec) | 0x1, 0xffffffec);
+#endif
+
return 0;
}

--
2.7.0