RISC-V: KVM: Use nacl_csr_xyz() for accessing AIA CSRs

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>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241020194734.58686-11-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>

diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c
index 8ffae0330c89a4e8ffaf71bd03421f2aed6d0926..dcced4db7fe8c3b6e4d1813a07b346fafad9270a 100644 (file)
--- 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 &&