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@xxxxxxxxxx> Co-developed-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> --- 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
