From: Anup Patel <apatel@ventanamicro.com>
To: kvm-riscv@lists.infradead.org
Subject: [PATCH v2] RISC-V: KVM: Redirect illegal instruction traps to guest
Date: Fri, 27 Jan 2023 16:59:34 +0530 [thread overview]
Message-ID: <20230127112934.2749592-1-apatel@ventanamicro.com> (raw)
From: Andy Chiu <andy.chiu@sifive.com>
The M-mode redirects an unhandled illegal instruction trap back
to S-mode. However, KVM running in HS-mode terminates the VS-mode
software when it receives illegal instruction trap. Instead, KVM
should redirect the illegal instruction trap back to VS-mode, and
let VS-mode trap handler decide the next step. This futher allows
guest kernel to implement on-demand enabling of vector extension
for a guest user space process upon first-use.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/kvm/vcpu_exit.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index c9f741ab26f5..4ea101a73d8b 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -160,6 +160,9 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
/* Set Guest PC to Guest exception vector */
vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC);
+
+ /* Set Guest privilege mode to supervisor */
+ vcpu->arch.guest_context.sstatus |= SR_SPP;
}
/*
@@ -179,6 +182,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
ret = -EFAULT;
run->exit_reason = KVM_EXIT_UNKNOWN;
switch (trap->scause) {
+ case EXC_INST_ILLEGAL:
+ if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
+ kvm_riscv_vcpu_trap_redirect(vcpu, trap);
+ ret = 1;
+ }
+ break;
case EXC_VIRTUAL_INST_FAULT:
if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap);
--
2.34.1
WARNING: multiple messages have this Message-ID (diff)
From: Anup Patel <apatel@ventanamicro.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Atish Patra <atishp@atishpatra.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Andrew Jones <ajones@ventanamicro.com>,
Anup Patel <anup@brainfault.org>,
kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Andy Chiu <andy.chiu@sifive.com>,
Anup Patel <apatel@ventanamicro.com>
Subject: [PATCH v2] RISC-V: KVM: Redirect illegal instruction traps to guest
Date: Fri, 27 Jan 2023 16:59:34 +0530 [thread overview]
Message-ID: <20230127112934.2749592-1-apatel@ventanamicro.com> (raw)
From: Andy Chiu <andy.chiu@sifive.com>
The M-mode redirects an unhandled illegal instruction trap back
to S-mode. However, KVM running in HS-mode terminates the VS-mode
software when it receives illegal instruction trap. Instead, KVM
should redirect the illegal instruction trap back to VS-mode, and
let VS-mode trap handler decide the next step. This futher allows
guest kernel to implement on-demand enabling of vector extension
for a guest user space process upon first-use.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/kvm/vcpu_exit.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index c9f741ab26f5..4ea101a73d8b 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -160,6 +160,9 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
/* Set Guest PC to Guest exception vector */
vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC);
+
+ /* Set Guest privilege mode to supervisor */
+ vcpu->arch.guest_context.sstatus |= SR_SPP;
}
/*
@@ -179,6 +182,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
ret = -EFAULT;
run->exit_reason = KVM_EXIT_UNKNOWN;
switch (trap->scause) {
+ case EXC_INST_ILLEGAL:
+ if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
+ kvm_riscv_vcpu_trap_redirect(vcpu, trap);
+ ret = 1;
+ }
+ break;
case EXC_VIRTUAL_INST_FAULT:
if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap);
--
2.34.1
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
WARNING: multiple messages have this Message-ID (diff)
From: Anup Patel <apatel@ventanamicro.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Atish Patra <atishp@atishpatra.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Andrew Jones <ajones@ventanamicro.com>,
Anup Patel <anup@brainfault.org>,
kvm@vger.kernel.org, kvm-riscv@lists.infradead.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Andy Chiu <andy.chiu@sifive.com>,
Anup Patel <apatel@ventanamicro.com>
Subject: [PATCH v2] RISC-V: KVM: Redirect illegal instruction traps to guest
Date: Fri, 27 Jan 2023 16:59:34 +0530 [thread overview]
Message-ID: <20230127112934.2749592-1-apatel@ventanamicro.com> (raw)
From: Andy Chiu <andy.chiu@sifive.com>
The M-mode redirects an unhandled illegal instruction trap back
to S-mode. However, KVM running in HS-mode terminates the VS-mode
software when it receives illegal instruction trap. Instead, KVM
should redirect the illegal instruction trap back to VS-mode, and
let VS-mode trap handler decide the next step. This futher allows
guest kernel to implement on-demand enabling of vector extension
for a guest user space process upon first-use.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
arch/riscv/kvm/vcpu_exit.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index c9f741ab26f5..4ea101a73d8b 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -160,6 +160,9 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
/* Set Guest PC to Guest exception vector */
vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC);
+
+ /* Set Guest privilege mode to supervisor */
+ vcpu->arch.guest_context.sstatus |= SR_SPP;
}
/*
@@ -179,6 +182,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
ret = -EFAULT;
run->exit_reason = KVM_EXIT_UNKNOWN;
switch (trap->scause) {
+ case EXC_INST_ILLEGAL:
+ if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {
+ kvm_riscv_vcpu_trap_redirect(vcpu, trap);
+ ret = 1;
+ }
+ break;
case EXC_VIRTUAL_INST_FAULT:
if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap);
--
2.34.1
next reply other threads:[~2023-01-27 11:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 11:29 Anup Patel [this message]
2023-01-27 11:29 ` [PATCH v2] RISC-V: KVM: Redirect illegal instruction traps to guest Anup Patel
2023-01-27 11:29 ` Anup Patel
2023-01-27 12:05 ` Andrew Jones
2023-01-27 12:05 ` Andrew Jones
2023-01-27 12:05 ` Andrew Jones
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