Currently each character of a string is term_putc()ed individually. This
causes a round trip into opensbi for each char. Very inefficient
especially since the interface term_putc() does accept a count.
This patch passes a count to term_putc() in the
SBI_EXT_DBCN_CONSOLE_WRITE path.
Signed-off-by: Cyril Bur <cyrilbur@xxxxxxxxxxxxxxx>
---
riscv/kvm-cpu.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/riscv/kvm-cpu.c b/riscv/kvm-cpu.c
index 0c171da..84d35f7 100644
--- a/riscv/kvm-cpu.c
+++ b/riscv/kvm-cpu.c
@@ -172,21 +172,23 @@ static bool kvm_cpu_riscv_sbi(struct kvm_cpu *vcpu)
str_start = guest_flat_to_host(vcpu->kvm, addr);
addr += vcpu->kvm_run->riscv_sbi.args[0] - 1;
str_end = guest_flat_to_host(vcpu->kvm, addr);
- if (!str_start || !str_end) {
+ if (!str_start || !str_end || str_start > str_end) {
vcpu->kvm_run->riscv_sbi.ret[0] =
SBI_ERR_INVALID_PARAM;
break;
}
+ if (vcpu->kvm_run->riscv_sbi.function_id ==
+ SBI_EXT_DBCN_CONSOLE_WRITE) {
+ int length = (str_end - str_start) + 1;
+
+ length = term_putc(str_start, length, 0);
+ vcpu->kvm_run->riscv_sbi.ret[1] = length;
+ break;
+ }
+ /* This will be SBI_EXT_DBCN_CONSOLE_READ */
vcpu->kvm_run->riscv_sbi.ret[1] = 0;
- while (str_start <= str_end) {
- if (vcpu->kvm_run->riscv_sbi.function_id ==
- SBI_EXT_DBCN_CONSOLE_WRITE) {
- term_putc(str_start, 1, 0);
- } else {
- if (!term_readable(0))
- break;
- *str_start = term_getc(vcpu->kvm, 0);
- }
+ while (str_start <= str_end && term_readable(0)) {
+ *str_start = term_getc(vcpu->kvm, 0);
vcpu->kvm_run->riscv_sbi.ret[1]++;
str_start++;
}
--
2.34.1
