* [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest
2023-01-28 8:28 [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Anup Patel
@ 2023-01-28 8:28 ` Anup Patel
2023-01-31 8:41 ` Atish Patra
2023-02-02 8:49 ` Anup Patel
2023-01-28 13:08 ` [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Andrew Jones
` (2 subsequent siblings)
3 siblings, 2 replies; 7+ messages in thread
From: Anup Patel @ 2023-01-28 8:28 UTC (permalink / raw)
To: Paolo Bonzini, Atish Patra
Cc: Palmer Dabbelt, Paul Walmsley, Andrew Jones, Anup Patel, kvm,
kvm-riscv, linux-riscv, linux-kernel, Andy Chiu, Anup Patel
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>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/kvm/vcpu_exit.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index af7c4bc07929..4ea101a73d8b 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -182,6 +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
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest
2023-01-28 8:28 ` [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest Anup Patel
@ 2023-01-31 8:41 ` Atish Patra
2023-02-02 8:49 ` Anup Patel
1 sibling, 0 replies; 7+ messages in thread
From: Atish Patra @ 2023-01-31 8:41 UTC (permalink / raw)
To: Anup Patel
Cc: Paolo Bonzini, Palmer Dabbelt, Paul Walmsley, Andrew Jones,
Anup Patel, kvm, kvm-riscv, linux-riscv, linux-kernel, Andy Chiu
On Sat, Jan 28, 2023 at 12:29 AM Anup Patel <apatel@ventanamicro.com> wrote:
>
> 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>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> ---
> arch/riscv/kvm/vcpu_exit.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index af7c4bc07929..4ea101a73d8b 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -182,6 +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
>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
--
Regards,
Atish
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest
2023-01-28 8:28 ` [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest Anup Patel
2023-01-31 8:41 ` Atish Patra
@ 2023-02-02 8:49 ` Anup Patel
1 sibling, 0 replies; 7+ messages in thread
From: Anup Patel @ 2023-02-02 8:49 UTC (permalink / raw)
To: Anup Patel
Cc: Paolo Bonzini, Atish Patra, Palmer Dabbelt, Paul Walmsley,
Andrew Jones, kvm, kvm-riscv, linux-riscv, linux-kernel,
Andy Chiu
On Sat, Jan 28, 2023 at 1:59 PM Anup Patel <apatel@ventanamicro.com> wrote:
>
> 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>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Queued this patch for Linux-6.3
Thanks,
Anup
> ---
> arch/riscv/kvm/vcpu_exit.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index af7c4bc07929..4ea101a73d8b 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -182,6 +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
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect()
2023-01-28 8:28 [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Anup Patel
2023-01-28 8:28 ` [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest Anup Patel
@ 2023-01-28 13:08 ` Andrew Jones
2023-01-31 8:41 ` Atish Patra
2023-02-02 8:49 ` Anup Patel
3 siblings, 0 replies; 7+ messages in thread
From: Andrew Jones @ 2023-01-28 13:08 UTC (permalink / raw)
To: Anup Patel
Cc: Paolo Bonzini, Atish Patra, Palmer Dabbelt, Paul Walmsley,
Anup Patel, kvm, kvm-riscv, linux-riscv, linux-kernel
On Sat, Jan 28, 2023 at 01:58:46PM +0530, Anup Patel wrote:
> The kvm_riscv_vcpu_trap_redirect() should set guest privilege mode
> to supervisor mode because guest traps/interrupts are always handled
> in virtual supervisor mode.
>
> Fixes: 9f7013265112 ("RISC-V: KVM: Handle MMIO exits for VCPU")
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
> arch/riscv/kvm/vcpu_exit.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index c9f741ab26f5..af7c4bc07929 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;
> }
>
> /*
> --
> 2.34.1
>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Thanks,
drew
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect()
2023-01-28 8:28 [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Anup Patel
2023-01-28 8:28 ` [PATCH v3 2/2] RISC-V: KVM: Redirect illegal instruction traps to guest Anup Patel
2023-01-28 13:08 ` [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Andrew Jones
@ 2023-01-31 8:41 ` Atish Patra
2023-02-02 8:49 ` Anup Patel
3 siblings, 0 replies; 7+ messages in thread
From: Atish Patra @ 2023-01-31 8:41 UTC (permalink / raw)
To: Anup Patel
Cc: Paolo Bonzini, Palmer Dabbelt, Paul Walmsley, Andrew Jones,
Anup Patel, kvm, kvm-riscv, linux-riscv, linux-kernel
On Sat, Jan 28, 2023 at 12:28 AM Anup Patel <apatel@ventanamicro.com> wrote:
>
> The kvm_riscv_vcpu_trap_redirect() should set guest privilege mode
> to supervisor mode because guest traps/interrupts are always handled
> in virtual supervisor mode.
>
> Fixes: 9f7013265112 ("RISC-V: KVM: Handle MMIO exits for VCPU")
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
> arch/riscv/kvm/vcpu_exit.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index c9f741ab26f5..af7c4bc07929 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;
> }
>
> /*
> --
> 2.34.1
>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
--
Regards,
Atish
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect()
2023-01-28 8:28 [PATCH v3 1/2] RISC-V: KVM: Fix privilege mode setting in kvm_riscv_vcpu_trap_redirect() Anup Patel
` (2 preceding siblings ...)
2023-01-31 8:41 ` Atish Patra
@ 2023-02-02 8:49 ` Anup Patel
3 siblings, 0 replies; 7+ messages in thread
From: Anup Patel @ 2023-02-02 8:49 UTC (permalink / raw)
To: Anup Patel
Cc: Paolo Bonzini, Atish Patra, Palmer Dabbelt, Paul Walmsley,
Andrew Jones, kvm, kvm-riscv, linux-riscv, linux-kernel
On Sat, Jan 28, 2023 at 1:58 PM Anup Patel <apatel@ventanamicro.com> wrote:
>
> The kvm_riscv_vcpu_trap_redirect() should set guest privilege mode
> to supervisor mode because guest traps/interrupts are always handled
> in virtual supervisor mode.
>
> Fixes: 9f7013265112 ("RISC-V: KVM: Handle MMIO exits for VCPU")
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Queued this patch for Linux-6.3
Thanks,
Anup
> ---
> arch/riscv/kvm/vcpu_exit.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index c9f741ab26f5..af7c4bc07929 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;
> }
>
> /*
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 7+ messages in thread