From: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
To: kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
kvm@vger.kernel.org
Cc: anup@brainfault.org, atishp@atishpatra.org,
ajones@ventanamicro.com,
Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Subject: [PATCH v4 08/10] RISC-V: KVM: avoid EBUSY when writing the same isa_ext val
Date: Thu, 3 Aug 2023 13:33:00 -0300 [thread overview]
Message-ID: <20230803163302.445167-9-dbarboza@ventanamicro.com> (raw)
In-Reply-To: <20230803163302.445167-1-dbarboza@ventanamicro.com>
riscv_vcpu_set_isa_ext_single() will prevent any write of isa_ext regs
if the vcpu already started spinning.
But if there's no extension state (enabled/disabled) made by the
userspace, there's no need to -EBUSY out - we can treat the operation as
a no-op.
zicbom/zicboz_block_size, ISA config reg and mvendorid/march/mimpid
already works in a more permissive manner w.r.t userspace writes being a
no-op, so let's do the same with isa_ext writes.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
---
arch/riscv/kvm/vcpu_onereg.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c
index 81cb6b2784db..989ea32dbcbe 100644
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
@@ -482,6 +482,9 @@ static int riscv_vcpu_set_isa_ext_single(struct kvm_vcpu *vcpu,
if (!__riscv_isa_extension_available(NULL, host_isa_ext))
return -ENOENT;
+ if (reg_val == test_bit(host_isa_ext, vcpu->arch.isa))
+ return 0;
+
if (!vcpu->arch.ran_atleast_once) {
/*
* All multi-letter extension and a few single letter
--
2.41.0
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next prev parent reply other threads:[~2023-08-03 16:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-03 16:32 [PATCH v4 00/10] RISC-V: KVM: change get_reg/set_reg error code Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 01/10] RISC-V: KVM: return ENOENT in *_one_reg() when reg is unknown Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 02/10] RISC-V: KVM: use ENOENT in *_one_reg() when extension is unavailable Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 03/10] RISC-V: KVM: do not EOPNOTSUPP in set_one_reg() zicbo(m|z) Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 04/10] RISC-V: KVM: do not EOPNOTSUPP in set KVM_REG_RISCV_TIMER_REG Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 05/10] RISC-V: KVM: use EBUSY when !vcpu->arch.ran_atleast_once Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 06/10] RISC-V: KVM: avoid EBUSY when writing same ISA val Daniel Henrique Barboza
2023-08-03 16:32 ` [PATCH v4 07/10] RISC-V: KVM: avoid EBUSY when writing the same machine ID val Daniel Henrique Barboza
2023-08-03 16:33 ` Daniel Henrique Barboza [this message]
2023-08-03 16:33 ` [PATCH v4 09/10] RISC-V: KVM: Improve vector save/restore errors Daniel Henrique Barboza
2023-08-03 17:05 ` Andrew Jones
2023-08-03 17:16 ` Andrew Jones
2023-08-03 16:33 ` [PATCH v4 10/10] docs: kvm: riscv: document EBUSY in KVM_SET_ONE_REG Daniel Henrique Barboza
2023-08-03 16:56 ` [PATCH v4 00/10] RISC-V: KVM: change get_reg/set_reg error code Andrew Jones
2023-08-04 9:11 ` Anup Patel
2023-08-05 16:32 ` Anup Patel
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