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[RFC,18/48] RISC-V: KVM: Skip TLB management for TVMs

Message ID 20230419221716.3603068-19-atishp@rivosinc.com (mailing list archive)
State Superseded
Headers show
Series RISC-V CoVE support | expand

Checks

Context Check Description
conchuod/tree_selection fail Failed to apply to next/pending-fixes or riscv/for-next

Commit Message

Atish Kumar Patra April 19, 2023, 10:16 p.m. UTC 
TSM manages the tlb entries for the TVMs. Thus, host can ignore
all the hfence requests or tlb updates for confidential guests.
Most of the hfence requests happen through vcpu requests which
are skipped for TVMs. Thus, we just need to take care of the
invocation from tlb management here.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 arch/riscv/kvm/tlb.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/riscv/kvm/tlb.c b/arch/riscv/kvm/tlb.c
index dff37b57..b007c02 100644
--- a/arch/riscv/kvm/tlb.c
+++ b/arch/riscv/kvm/tlb.c
@@ -15,6 +15,7 @@ 
 #include <asm/hwcap.h>
 #include <asm/insn-def.h>
 #include <asm/kvm_nacl.h>
+#include <asm/kvm_cove.h>
 
 #define has_svinval()	riscv_has_extension_unlikely(RISCV_ISA_EXT_SVINVAL)
 
@@ -72,6 +73,14 @@  void kvm_riscv_local_hfence_gvma_gpa(gpa_t gpa, gpa_t gpsz,
 
 void kvm_riscv_local_hfence_gvma_all(void)
 {
+	/* For TVMs, TSM will take care of hfence.
+	 * TODO: We can't skip unconditionally if cove is enabled
+	 * as the host may be running in HS-mode and need to issue hfence
+	 * for legacy VMs.
+	 */
+	if (kvm_riscv_cove_enabled())
+		return;
+
 	asm volatile(HFENCE_GVMA(zero, zero) : : : "memory");
 }
 
@@ -160,7 +169,7 @@  void kvm_riscv_local_tlb_sanitize(struct kvm_vcpu *vcpu)
 {
 	unsigned long vmid;
 
-	if (!kvm_riscv_gstage_vmid_bits() ||
+	if (is_cove_vcpu(vcpu) || !kvm_riscv_gstage_vmid_bits() ||
 	    vcpu->arch.last_exit_cpu == vcpu->cpu)
 		return;