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[08/15] KVM: MIPS: Use root tlb to control guest's CCA for Loongson-3

Message ID 1586763024-12197-9-git-send-email-chenhc@lemote.com (mailing list archive)
State Superseded
Headers show
Series KVM: MIPS: Add Loongson-3 support (Host Side) | expand

Commit Message

Huacai Chen April 13, 2020, 7:30 a.m. UTC 
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 | 4 ++++
 1 file changed, 4 insertions(+)
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Patch

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;
 }