diff mbox series

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

Message ID 20240415064905.25184-1-yongxuan.wang@sifive.com (mailing list archive)
State New, archived
Headers show
Series [1/1] RISC-V: KVM: No need to use mask when hart-index-bit is 0 | expand

Commit Message

Yong-Xuan Wang April 15, 2024, 6:49 a.m. UTC
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 <yongxuan.wang@sifive.com>
---
 arch/riscv/kvm/aia_device.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Yong-Xuan Wang May 22, 2024, 8:24 a.m. UTC | #1
Ping

On Mon, Apr 15, 2024 at 2:49 PM Yong-Xuan Wang <yongxuan.wang@sifive.com> 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 <yongxuan.wang@sifive.com>
> ---
>  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
>
Andrew Jones May 22, 2024, 9 a.m. UTC | #2
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 <yongxuan.wang@sifive.com>
> ---
>  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 <ajones@ventanamicro.com>
Anup Patel May 31, 2024, 4:34 a.m. UTC | #3
On Mon, Apr 15, 2024 at 12:19 PM Yong-Xuan Wang
<yongxuan.wang@sifive.com> 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 <yongxuan.wang@sifive.com>

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
>
diff mbox series

Patch

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);