[PATCH 3/4] riscv: KVM: Apply insn-def to hfence encodings

Andrew Jones
2022-08-19T14:03:23Z

Introduce hfence instruction encodings and apply them to KVM's use.
With the self-documenting nature of the instruction encoding macros,
and a spec always within arm's reach, it's safe to remove the
comments, so we do that too.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/insn-def.h | 8 ++
arch/riscv/kvm/tlb.c | 117 ++++--------------------------
2 files changed, 21 insertions(+), 104 deletions(-)

diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
index 4cd0208068dd..cd1c0d365f47 100644
--- a/arch/riscv/include/asm/insn-def.h
+++ b/arch/riscv/include/asm/insn-def.h
@@ -79,4 +79,12 @@
#define RS1(v) __REG(v)
#define RS2(v) __REG(v)

+#define OPCODE_SYSTEM OPCODE(115)
+
+#define HFENCE_VVMA(vaddr, asid) \
+ INSN_R(OPCODE_SYSTEM, FUNC3(0), FUNC7(17), RD(0), vaddr, asid)
+
+#define HFENCE_GVMA(gaddr, vmid) \
+ INSN_R(OPCODE_SYSTEM, FUNC3(0), FUNC7(49), RD(0), gaddr, vmid)
+
#endif /* __ASM_INSN_DEF_H */
diff --git a/arch/riscv/kvm/tlb.c b/arch/riscv/kvm/tlb.c
index 1a76d0b1907d..f742a0d888e1 100644
--- a/arch/riscv/kvm/tlb.c
+++ b/arch/riscv/kvm/tlb.c
@@ -12,22 +12,7 @@
#include <linux/kvm_host.h>
#include <asm/cacheflush.h>
#include <asm/csr.h>
-
-/*
- * Instruction encoding of hfence.gvma is:
- * HFENCE.GVMA rs1, rs2
- * HFENCE.GVMA zero, rs2
- * HFENCE.GVMA rs1
- * HFENCE.GVMA
- *
- * rs1!=zero and rs2!=zero ==> HFENCE.GVMA rs1, rs2
- * rs1==zero and rs2!=zero ==> HFENCE.GVMA zero, rs2
- * rs1!=zero and rs2==zero ==> HFENCE.GVMA rs1
- * rs1==zero and rs2==zero ==> HFENCE.GVMA
- *
- * Instruction encoding of HFENCE.GVMA is:
- * 0110001 rs2(5) rs1(5) 000 00000 1110011
- */
+#include <asm/insn-def.h>

void kvm_riscv_local_hfence_gvma_vmid_gpa(unsigned long vmid,
gpa_t gpa, gpa_t gpsz,
@@ -41,31 +26,14 @@ void kvm_riscv_local_hfence_gvma_vmid_gpa(unsigned long vmid,
}

for (pos = gpa; pos < (gpa + gpsz); pos += BIT(order)) {
- /*
- * rs1 = a0 (GPA >> 2)
- * rs2 = a1 (VMID)
- * HFENCE.GVMA a0, a1
- * 0110001 01011 01010 000 00000 1110011
- */
- asm volatile ("srli a0, %0, 2\n"
- "add a1, %1, zero\n"
- ".word 0x62b50073\n"
- :: "r" (pos), "r" (vmid)
- : "a0", "a1", "memory");
+ asm volatile (HFENCE_GVMA("%0", "%1")
+ : : "r" (pos >> 2), "r" (vmid) : "memory");
}
}

void kvm_riscv_local_hfence_gvma_vmid_all(unsigned long vmid)
{
- /*
- * rs1 = zero
- * rs2 = a0 (VMID)
- * HFENCE.GVMA zero, a0
- * 0110001 01010 00000 000 00000 1110011
- */
- asm volatile ("add a0, %0, zero\n"
- ".word 0x62a00073\n"
- :: "r" (vmid) : "a0", "memory");
+ asm volatile(HFENCE_GVMA("zero", "%0") : : "r" (vmid) : "memory");
}

void kvm_riscv_local_hfence_gvma_gpa(gpa_t gpa, gpa_t gpsz,
@@ -79,45 +47,16 @@ void kvm_riscv_local_hfence_gvma_gpa(gpa_t gpa, gpa_t gpsz,
}

for (pos = gpa; pos < (gpa + gpsz); pos += BIT(order)) {
- /*
- * rs1 = a0 (GPA >> 2)
- * rs2 = zero
- * HFENCE.GVMA a0
- * 0110001 00000 01010 000 00000 1110011
- */
- asm volatile ("srli a0, %0, 2\n"
- ".word 0x62050073\n"
- :: "r" (pos) : "a0", "memory");
+ asm volatile(HFENCE_GVMA("%0", "zero")
+ : : "r" (pos >> 2) : "memory");
}
}

void kvm_riscv_local_hfence_gvma_all(void)
{
- /*
- * rs1 = zero
- * rs2 = zero
- * HFENCE.GVMA
- * 0110001 00000 00000 000 00000 1110011
- */
- asm volatile (".word 0x62000073" ::: "memory");
+ asm volatile(HFENCE_GVMA("zero", "zero") : : : "memory");
}

-/*
- * Instruction encoding of hfence.gvma is:
- * HFENCE.VVMA rs1, rs2
- * HFENCE.VVMA zero, rs2
- * HFENCE.VVMA rs1
- * HFENCE.VVMA
- *
- * rs1!=zero and rs2!=zero ==> HFENCE.VVMA rs1, rs2
- * rs1==zero and rs2!=zero ==> HFENCE.VVMA zero, rs2
- * rs1!=zero and rs2==zero ==> HFENCE.VVMA rs1
- * rs1==zero and rs2==zero ==> HFENCE.VVMA
- *
- * Instruction encoding of HFENCE.VVMA is:
- * 0010001 rs2(5) rs1(5) 000 00000 1110011
- */
-
void kvm_riscv_local_hfence_vvma_asid_gva(unsigned long vmid,
unsigned long asid,
unsigned long gva,
@@ -134,17 +73,8 @@ void kvm_riscv_local_hfence_vvma_asid_gva(unsigned long vmid,
hgatp = csr_swap(CSR_HGATP, vmid << HGATP_VMID_SHIFT);

for (pos = gva; pos < (gva + gvsz); pos += BIT(order)) {
- /*
- * rs1 = a0 (GVA)
- * rs2 = a1 (ASID)
- * HFENCE.VVMA a0, a1
- * 0010001 01011 01010 000 00000 1110011
- */
- asm volatile ("add a0, %0, zero\n"
- "add a1, %1, zero\n"
- ".word 0x22b50073\n"
- :: "r" (pos), "r" (asid)
- : "a0", "a1", "memory");
+ asm volatile(HFENCE_VVMA("%0", "%1")
+ : : "r" (pos), "r" (asid) : "memory");
}

csr_write(CSR_HGATP, hgatp);
@@ -157,15 +87,7 @@ void kvm_riscv_local_hfence_vvma_asid_all(unsigned long vmid,

hgatp = csr_swap(CSR_HGATP, vmid << HGATP_VMID_SHIFT);

- /*
- * rs1 = zero
- * rs2 = a0 (ASID)
- * HFENCE.VVMA zero, a0
- * 0010001 01010 00000 000 00000 1110011
- */
- asm volatile ("add a0, %0, zero\n"
- ".word 0x22a00073\n"
- :: "r" (asid) : "a0", "memory");
+ asm volatile(HFENCE_VVMA("zero", "%0") : : "r" (asid) : "memory");

csr_write(CSR_HGATP, hgatp);
}
@@ -184,15 +106,8 @@ void kvm_riscv_local_hfence_vvma_gva(unsigned long vmid,
hgatp = csr_swap(CSR_HGATP, vmid << HGATP_VMID_SHIFT);

for (pos = gva; pos < (gva + gvsz); pos += BIT(order)) {
- /*
- * rs1 = a0 (GVA)
- * rs2 = zero
- * HFENCE.VVMA a0
- * 0010001 00000 01010 000 00000 1110011
- */
- asm volatile ("add a0, %0, zero\n"
- ".word 0x22050073\n"
- :: "r" (pos) : "a0", "memory");
+ asm volatile(HFENCE_VVMA("%0", "zero")
+ : : "r" (pos) : "memory");
}

csr_write(CSR_HGATP, hgatp);
@@ -204,13 +119,7 @@ void kvm_riscv_local_hfence_vvma_all(unsigned long vmid)

hgatp = csr_swap(CSR_HGATP, vmid << HGATP_VMID_SHIFT);

- /*
- * rs1 = zero
- * rs2 = zero
- * HFENCE.VVMA
- * 0010001 00000 00000 000 00000 1110011
- */
- asm volatile (".word 0x22000073" ::: "memory");
+ asm volatile(HFENCE_VVMA("zero", "zero") : : : "memory");

csr_write(CSR_HGATP, hgatp);
}
--
2.37.1