CC maintainers and Thomas.
This fix should be 20.11. The issue is seen multiple times a day under ~20G
traffic with stats collection once per second.
Igor
On Tue, Nov 17, 2020 at 11:56 AM Igor Ryzhov <iryz...@nfware.com> wrote:
> When low and high registers are read separately, this opens the door to
> a race condition:
> - low register is read
> - NIC updates the registers
> - high register is read
>
> Because of this, we may end up with an incorrect counter value.
> Let's read the registers in one shot, as it is done in Linux kernel
> since the introduction of the i40e driver.
>
> Fixes: 4861cde46116 ("i40e: new poll mode driver")
> Cc: sta...@dpdk.org
> Signed-off-by: Igor Ryzhov <iryz...@nfware.com>
> ---
> drivers/net/i40e/base/i40e_osdep.h | 10 ++++++++++
> drivers/net/i40e/i40e_ethdev.c | 10 +++++++---
> 2 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/i40e/base/i40e_osdep.h
> b/drivers/net/i40e/base/i40e_osdep.h
> index 64b15e1b6138..ebd687240006 100644
> --- a/drivers/net/i40e/base/i40e_osdep.h
> +++ b/drivers/net/i40e/base/i40e_osdep.h
> @@ -133,6 +133,14 @@ static inline uint32_t i40e_read_addr(volatile void
> *addr)
> return rte_le_to_cpu_32(I40E_PCI_REG(addr));
> }
>
> +#define I40E_PCI_REG64(reg) rte_read64(reg)
> +#define I40E_PCI_REG64_ADDR(a, reg) \
> + ((volatile uint64_t *)((char *)(a)->hw_addr + (reg)))
> +static inline uint64_t i40e_read64_addr(volatile void *addr)
> +{
> + return rte_le_to_cpu_64(I40E_PCI_REG64(addr));
> +}
> +
> #define I40E_PCI_REG_WRITE(reg, value) \
> rte_write32((rte_cpu_to_le_32(value)), reg)
> #define I40E_PCI_REG_WRITE_RELAXED(reg, value) \
> @@ -145,6 +153,8 @@ static inline uint32_t i40e_read_addr(volatile void
> *addr)
> #define I40E_WRITE_REG(hw, reg, value) \
> I40E_PCI_REG_WRITE(I40E_PCI_REG_ADDR((hw), (reg)), (value))
>
> +#define I40E_READ_REG64(hw, reg)
> i40e_read64_addr(I40E_PCI_REG64_ADDR((hw), (reg)))
> +
> #define rd32(a, reg) i40e_read_addr(I40E_PCI_REG_ADDR((a), (reg)))
> #define wr32(a, reg, value) \
> I40E_PCI_REG_WRITE(I40E_PCI_REG_ADDR((a), (reg)), (value))
> diff --git a/drivers/net/i40e/i40e_ethdev.c
> b/drivers/net/i40e/i40e_ethdev.c
> index 74f4ac1f9d4e..53b1e9b9e067 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -6451,9 +6451,13 @@ i40e_stat_update_48(struct i40e_hw *hw,
> {
> uint64_t new_data;
>
> - new_data = (uint64_t)I40E_READ_REG(hw, loreg);
> - new_data |= ((uint64_t)(I40E_READ_REG(hw, hireg) &
> - I40E_16_BIT_MASK)) << I40E_32_BIT_WIDTH;
> + if (hw->device_id == I40E_DEV_ID_QEMU) {
> + new_data = (uint64_t)I40E_READ_REG(hw, loreg);
> + new_data |= ((uint64_t)(I40E_READ_REG(hw, hireg) &
> + I40E_16_BIT_MASK)) << I40E_32_BIT_WIDTH;
> + } else {
> + new_data = I40E_READ_REG64(hw, loreg);
> + }
>
> if (!offset_loaded)
> *offset = new_data;
> --
> 2.29.2
>
>
