From: Yong-Xuan Wang <yongxuan.wang@sifive.com>
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: greentime.hu@sifive.com, vincent.chen@sifive.com,
frank.chang@sifive.com, jim.shu@sifive.com,
"Yong-Xuan Wang" <yongxuan.wang@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Alistair Francis" <alistair.francis@wdc.com>,
"Bin Meng" <bin.meng@windriver.com>,
"Weiwei Li" <liwei1518@gmail.com>,
"Daniel Henrique Barboza" <dbarboza@ventanamicro.com>,
"Liu Zhiwei" <zhiwei_liu@linux.alibaba.com>,
"Andrew Jones" <ajones@ventanamicro.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [PATCH 1/1] target/riscv/kvm.c: Fix the hart bit setting of AIA
Date: Mon, 15 Apr 2024 14:52:43 +0800 [thread overview]
Message-ID: <20240415065245.25455-1-yongxuan.wang@sifive.com> (raw)
The hart bit setting is different with Linux AIA driver[1] when the number
of hart is power of 2. For example, when the guest has 4 harts, the
estimated result of AIA driver is 2, whereas we pass 3 to RISC-V/KVM. Since
only 2 bits are needed to represent 4 harts, update the formula to get the
accurate result.
[1] https://lore.kernel.org/all/20240307140307.646078-1-apatel@ventanamicro.com/
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
---
target/riscv/kvm/kvm-cpu.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 6a6c6cae80f1..388c4ddaa145 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1642,7 +1642,14 @@ void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
}
}
- hart_bits = find_last_bit(&max_hart_per_socket, BITS_PER_LONG) + 1;
+
+ if (max_hart_per_socket > 1) {
+ max_hart_per_socket--;
+ hart_bits = find_last_bit(&max_hart_per_socket, BITS_PER_LONG) + 1;
+ } else {
+ hart_bits = 0;
+ }
+
ret = kvm_device_access(aia_fd, KVM_DEV_RISCV_AIA_GRP_CONFIG,
KVM_DEV_RISCV_AIA_CONFIG_HART_BITS,
&hart_bits, true, NULL);
--
2.17.1
next reply other threads:[~2024-04-15 6:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 6:52 Yong-Xuan Wang [this message]
2024-04-29 3:25 ` [PATCH 1/1] target/riscv/kvm.c: Fix the hart bit setting of AIA Alistair Francis
2024-05-07 10:12 ` Yong-Xuan Wang
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