2024-04-15 06:49:23

by Yong-Xuan Wang

Subject: [PATCH 1/1] RISC-V: KVM: No need to use mask when hart-index-bit is 0

When the maximum hart number within groups is 1, hart-index-bit is set to
0. Consequently, there is no need to restore the hart ID from IMSIC
addresses and hart-index-bit settings. Currently, QEMU and kvmtool do not
pass correct hart-index-bit values when the maximum hart number is a
power of 2, thereby avoiding this issue. Corresponding patches for QEMU
and kvmtool will also be dispatched.

Fixes: 89d01306e34d ("RISC-V: KVM: Implement device interface for AIA irqchip")
Signed-off-by: Yong-Xuan Wang <[email protected]>
---
arch/riscv/kvm/aia_device.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
index 0eb689351b7d..5cd407c6a8e4 100644
--- a/arch/riscv/kvm/aia_device.c
+++ b/arch/riscv/kvm/aia_device.c
@@ -237,10 +237,11 @@ static gpa_t aia_imsic_ppn(struct kvm_aia *aia, gpa_t addr)

static u32 aia_imsic_hart_index(struct kvm_aia *aia, gpa_t addr)
{
- u32 hart, group = 0;
+ u32 hart = 0, group = 0;

- hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
- GENMASK_ULL(aia->nr_hart_bits - 1, 0);
+ if (aia->nr_hart_bits)
+ hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
+ GENMASK_ULL(aia->nr_hart_bits - 1, 0);
if (aia->nr_group_bits)
group = (addr >> aia->nr_group_shift) &
GENMASK_ULL(aia->nr_group_bits - 1, 0);
--
2.17.1

2024-05-22 08:25:47

by Yong-Xuan Wang

Subject: Re: [PATCH 1/1] RISC-V: KVM: No need to use mask when hart-index-bit is 0

Ping

On Mon, Apr 15, 2024 at 2:49 PM Yong-Xuan Wang <[email protected]> wrote:
>
> When the maximum hart number within groups is 1, hart-index-bit is set to
> 0. Consequently, there is no need to restore the hart ID from IMSIC
> addresses and hart-index-bit settings. Currently, QEMU and kvmtool do not
> pass correct hart-index-bit values when the maximum hart number is a
> power of 2, thereby avoiding this issue. Corresponding patches for QEMU
> and kvmtool will also be dispatched.
>
> Fixes: 89d01306e34d ("RISC-V: KVM: Implement device interface for AIA irqchip")
> Signed-off-by: Yong-Xuan Wang <[email protected]>
> ---
> arch/riscv/kvm/aia_device.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> index 0eb689351b7d..5cd407c6a8e4 100644
> --- a/arch/riscv/kvm/aia_device.c
> +++ b/arch/riscv/kvm/aia_device.c
> @@ -237,10 +237,11 @@ static gpa_t aia_imsic_ppn(struct kvm_aia *aia, gpa_t addr)
>
> static u32 aia_imsic_hart_index(struct kvm_aia *aia, gpa_t addr)
> {
> - u32 hart, group = 0;
> + u32 hart = 0, group = 0;
>
> - hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> - GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> + if (aia->nr_hart_bits)
> + hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> + GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> if (aia->nr_group_bits)
> group = (addr >> aia->nr_group_shift) &
> GENMASK_ULL(aia->nr_group_bits - 1, 0);
> --
> 2.17.1
>

2024-05-22 09:00:26

by Andrew Jones

Subject: Re: [PATCH 1/1] RISC-V: KVM: No need to use mask when hart-index-bit is 0

On Mon, Apr 15, 2024 at 02:49:04PM GMT, Yong-Xuan Wang wrote:
> When the maximum hart number within groups is 1, hart-index-bit is set to
> 0. Consequently, there is no need to restore the hart ID from IMSIC
> addresses and hart-index-bit settings. Currently, QEMU and kvmtool do not
> pass correct hart-index-bit values when the maximum hart number is a
> power of 2, thereby avoiding this issue. Corresponding patches for QEMU
> and kvmtool will also be dispatched.
>
> Fixes: 89d01306e34d ("RISC-V: KVM: Implement device interface for AIA irqchip")
> Signed-off-by: Yong-Xuan Wang <[email protected]>
> ---
> arch/riscv/kvm/aia_device.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> index 0eb689351b7d..5cd407c6a8e4 100644
> --- a/arch/riscv/kvm/aia_device.c
> +++ b/arch/riscv/kvm/aia_device.c
> @@ -237,10 +237,11 @@ static gpa_t aia_imsic_ppn(struct kvm_aia *aia, gpa_t addr)
>
> static u32 aia_imsic_hart_index(struct kvm_aia *aia, gpa_t addr)
> {
> - u32 hart, group = 0;
> + u32 hart = 0, group = 0;
>
> - hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> - GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> + if (aia->nr_hart_bits)
> + hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> + GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> if (aia->nr_group_bits)
> group = (addr >> aia->nr_group_shift) &
> GENMASK_ULL(aia->nr_group_bits - 1, 0);
> --
> 2.17.1
>

Reviewed-by: Andrew Jones <[email protected]>

2024-05-31 06:34:46

by Anup Patel

Subject: Re: [PATCH 1/1] RISC-V: KVM: No need to use mask when hart-index-bit is 0

On Mon, Apr 15, 2024 at 12:19 PM Yong-Xuan Wang
<[email protected]> wrote:
>
> When the maximum hart number within groups is 1, hart-index-bit is set to
> 0. Consequently, there is no need to restore the hart ID from IMSIC
> addresses and hart-index-bit settings. Currently, QEMU and kvmtool do not
> pass correct hart-index-bit values when the maximum hart number is a
> power of 2, thereby avoiding this issue. Corresponding patches for QEMU
> and kvmtool will also be dispatched.
>
> Fixes: 89d01306e34d ("RISC-V: KVM: Implement device interface for AIA irqchip")
> Signed-off-by: Yong-Xuan Wang <[email protected]>

Queued this patch for Linux-6.10-rcX fixes.

Thanks,
Anup

> ---
> arch/riscv/kvm/aia_device.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> index 0eb689351b7d..5cd407c6a8e4 100644
> --- a/arch/riscv/kvm/aia_device.c
> +++ b/arch/riscv/kvm/aia_device.c
> @@ -237,10 +237,11 @@ static gpa_t aia_imsic_ppn(struct kvm_aia *aia, gpa_t addr)
>
> static u32 aia_imsic_hart_index(struct kvm_aia *aia, gpa_t addr)
> {
> - u32 hart, group = 0;
> + u32 hart = 0, group = 0;
>
> - hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> - GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> + if (aia->nr_hart_bits)
> + hart = (addr >> (aia->nr_guest_bits + IMSIC_MMIO_PAGE_SHIFT)) &
> + GENMASK_ULL(aia->nr_hart_bits - 1, 0);
> if (aia->nr_group_bits)
> group = (addr >> aia->nr_group_shift) &
> GENMASK_ULL(aia->nr_group_bits - 1, 0);
> --
> 2.17.1
>