[PATCH 10/13] RISC-V: KVM: Use nacl_csr_xyz() for accessing AIA CSRs

Anup Patel
2024-07-19T16:10:00Z

When running under some other hypervisor, prefer nacl_csr_xyz()
for accessing AIA CSRs in the run-loop. This makes CSR access
faster whenever SBI nested acceleration is available.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/kvm/aia.c | 97 ++++++++++++++++++++++++++++----------------
1 file changed, 63 insertions(+), 34 deletions(-)

diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
index 8ffae0330c89..dcced4db7fe8 100644
--- a/arch/riscv/kvm/aia.c
+++ b/arch/riscv/kvm/aia.c
@@ -16,6 +16,7 @@
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <asm/cpufeature.h>
+#include <asm/kvm_nacl.h>

struct aia_hgei_control {
raw_spinlock_t lock;
@@ -88,7 +89,7 @@ void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu)
struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;

if (kvm_riscv_aia_available())
- csr->vsieh = csr_read(CSR_VSIEH);
+ csr->vsieh = ncsr_read(CSR_VSIEH);
}
#endif

@@ -115,7 +116,7 @@ bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask)

hgei = aia_find_hgei(vcpu);
if (hgei > 0)
- return !!(csr_read(CSR_HGEIP) & BIT(hgei));
+ return !!(ncsr_read(CSR_HGEIP) & BIT(hgei));

return false;
}
@@ -128,45 +129,73 @@ void kvm_riscv_vcpu_aia_update_hvip(struct kvm_vcpu *vcpu)
return;

#ifdef CONFIG_32BIT
- csr_write(CSR_HVIPH, vcpu->arch.aia_context.guest_csr.hviph);
+ ncsr_write(CSR_HVIPH, vcpu->arch.aia_context.guest_csr.hviph);
#endif
- csr_write(CSR_HVICTL, aia_hvictl_value(!!(csr->hvip & BIT(IRQ_VS_EXT))));
+ ncsr_write(CSR_HVICTL, aia_hvictl_value(!!(csr->hvip & BIT(IRQ_VS_EXT))));
}

void kvm_riscv_vcpu_aia_load(struct kvm_vcpu *vcpu, int cpu)
{
struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;
+ void *nsh;

if (!kvm_riscv_aia_available())
return;

- csr_write(CSR_VSISELECT, csr->vsiselect);
- csr_write(CSR_HVIPRIO1, csr->hviprio1);
- csr_write(CSR_HVIPRIO2, csr->hviprio2);
+ if (kvm_riscv_nacl_sync_csr_available()) {
+ nsh = nacl_shmem();
+ nacl_csr_write(nsh, CSR_VSISELECT, csr->vsiselect);
+ nacl_csr_write(nsh, CSR_HVIPRIO1, csr->hviprio1);
+ nacl_csr_write(nsh, CSR_HVIPRIO2, csr->hviprio2);
+#ifdef CONFIG_32BIT
+ nacl_csr_write(nsh, CSR_VSIEH, csr->vsieh);
+ nacl_csr_write(nsh, CSR_HVIPH, csr->hviph);
+ nacl_csr_write(nsh, CSR_HVIPRIO1H, csr->hviprio1h);
+ nacl_csr_write(nsh, CSR_HVIPRIO2H, csr->hviprio2h);
+#endif
+ } else {
+ csr_write(CSR_VSISELECT, csr->vsiselect);
+ csr_write(CSR_HVIPRIO1, csr->hviprio1);
+ csr_write(CSR_HVIPRIO2, csr->hviprio2);
#ifdef CONFIG_32BIT
- csr_write(CSR_VSIEH, csr->vsieh);
- csr_write(CSR_HVIPH, csr->hviph);
- csr_write(CSR_HVIPRIO1H, csr->hviprio1h);
- csr_write(CSR_HVIPRIO2H, csr->hviprio2h);
+ csr_write(CSR_VSIEH, csr->vsieh);
+ csr_write(CSR_HVIPH, csr->hviph);
+ csr_write(CSR_HVIPRIO1H, csr->hviprio1h);
+ csr_write(CSR_HVIPRIO2H, csr->hviprio2h);
#endif
+ }
}

void kvm_riscv_vcpu_aia_put(struct kvm_vcpu *vcpu)
{
struct kvm_vcpu_aia_csr *csr = &vcpu->arch.aia_context.guest_csr;
+ void *nsh;

if (!kvm_riscv_aia_available())
return;

- csr->vsiselect = csr_read(CSR_VSISELECT);
- csr->hviprio1 = csr_read(CSR_HVIPRIO1);
- csr->hviprio2 = csr_read(CSR_HVIPRIO2);
+ if (kvm_riscv_nacl_available()) {
+ nsh = nacl_shmem();
+ csr->vsiselect = nacl_csr_read(nsh, CSR_VSISELECT);
+ csr->hviprio1 = nacl_csr_read(nsh, CSR_HVIPRIO1);
+ csr->hviprio2 = nacl_csr_read(nsh, CSR_HVIPRIO2);
#ifdef CONFIG_32BIT
- csr->vsieh = csr_read(CSR_VSIEH);
- csr->hviph = csr_read(CSR_HVIPH);
- csr->hviprio1h = csr_read(CSR_HVIPRIO1H);
- csr->hviprio2h = csr_read(CSR_HVIPRIO2H);
+ csr->vsieh = nacl_csr_read(nsh, CSR_VSIEH);
+ csr->hviph = nacl_csr_read(nsh, CSR_HVIPH);
+ csr->hviprio1h = nacl_csr_read(nsh, CSR_HVIPRIO1H);
+ csr->hviprio2h = nacl_csr_read(nsh, CSR_HVIPRIO2H);
#endif
+ } else {
+ csr->vsiselect = csr_read(CSR_VSISELECT);
+ csr->hviprio1 = csr_read(CSR_HVIPRIO1);
+ csr->hviprio2 = csr_read(CSR_HVIPRIO2);
+#ifdef CONFIG_32BIT
+ csr->vsieh = csr_read(CSR_VSIEH);
+ csr->hviph = csr_read(CSR_HVIPH);
+ csr->hviprio1h = csr_read(CSR_HVIPRIO1H);
+ csr->hviprio2h = csr_read(CSR_HVIPRIO2H);
+#endif
+ }
}

int kvm_riscv_vcpu_aia_get_csr(struct kvm_vcpu *vcpu,
@@ -250,20 +279,20 @@ static u8 aia_get_iprio8(struct kvm_vcpu *vcpu, unsigned int irq)

switch (bitpos / BITS_PER_LONG) {
case 0:
- hviprio = csr_read(CSR_HVIPRIO1);
+ hviprio = ncsr_read(CSR_HVIPRIO1);
break;
case 1:
#ifndef CONFIG_32BIT
- hviprio = csr_read(CSR_HVIPRIO2);
+ hviprio = ncsr_read(CSR_HVIPRIO2);
break;
#else
- hviprio = csr_read(CSR_HVIPRIO1H);
+ hviprio = ncsr_read(CSR_HVIPRIO1H);
break;
case 2:
- hviprio = csr_read(CSR_HVIPRIO2);
+ hviprio = ncsr_read(CSR_HVIPRIO2);
break;
case 3:
- hviprio = csr_read(CSR_HVIPRIO2H);
+ hviprio = ncsr_read(CSR_HVIPRIO2H);
break;
#endif
default:
@@ -283,20 +312,20 @@ static void aia_set_iprio8(struct kvm_vcpu *vcpu, unsigned int irq, u8 prio)

switch (bitpos / BITS_PER_LONG) {
case 0:
- hviprio = csr_read(CSR_HVIPRIO1);
+ hviprio = ncsr_read(CSR_HVIPRIO1);
break;
case 1:
#ifndef CONFIG_32BIT
- hviprio = csr_read(CSR_HVIPRIO2);
+ hviprio = ncsr_read(CSR_HVIPRIO2);
break;
#else
- hviprio = csr_read(CSR_HVIPRIO1H);
+ hviprio = ncsr_read(CSR_HVIPRIO1H);
break;
case 2:
- hviprio = csr_read(CSR_HVIPRIO2);
+ hviprio = ncsr_read(CSR_HVIPRIO2);
break;
case 3:
- hviprio = csr_read(CSR_HVIPRIO2H);
+ hviprio = ncsr_read(CSR_HVIPRIO2H);
break;
#endif
default:
@@ -308,20 +337,20 @@ static void aia_set_iprio8(struct kvm_vcpu *vcpu, unsigned int irq, u8 prio)

switch (bitpos / BITS_PER_LONG) {
case 0:
- csr_write(CSR_HVIPRIO1, hviprio);
+ ncsr_write(CSR_HVIPRIO1, hviprio);
break;
case 1:
#ifndef CONFIG_32BIT
- csr_write(CSR_HVIPRIO2, hviprio);
+ ncsr_write(CSR_HVIPRIO2, hviprio);
break;
#else
- csr_write(CSR_HVIPRIO1H, hviprio);
+ ncsr_write(CSR_HVIPRIO1H, hviprio);
break;
case 2:
- csr_write(CSR_HVIPRIO2, hviprio);
+ ncsr_write(CSR_HVIPRIO2, hviprio);
break;
case 3:
- csr_write(CSR_HVIPRIO2H, hviprio);
+ ncsr_write(CSR_HVIPRIO2H, hviprio);
break;
#endif
default:
@@ -377,7 +406,7 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num,
return KVM_INSN_ILLEGAL_TRAP;

/* First try to emulate in kernel space */
- isel = csr_read(CSR_VSISELECT) & ISELECT_MASK;
+ isel = ncsr_read(CSR_VSISELECT) & ISELECT_MASK;
if (isel >= ISELECT_IPRIO0 && isel <= ISELECT_IPRIO15)
return aia_rmw_iprio(vcpu, isel, val, new_val, wr_mask);
else if (isel >= IMSIC_FIRST && isel <= IMSIC_LAST &&
--
2.34.1