virtio_blk: set the zone write granularitygrafted

virtblk_read_zoned_limits() reads the write granularity that the device
reports in virtio_blk_zoned_characteristics and assigns it to the
physical block size and to io_min, but never to the limit that is named
after it. queue_limits.zone_write_granularity is left at zero, so
blk_validate_zoned_limits() raises it to the logical block size:

	if (lim->zone_write_granularity < lim->logical_block_size)
		lim->zone_write_granularity = lim->logical_block_size;

A device that reports a granularity coarser than its logical block size,
which is what the field exists to express, therefore has it silently
reduced. A 512e host managed disk passed through to a guest reports a
logical block size of 512 and a write granularity of 4096, and the guest
ends up with a zone write granularity of 512.

bio_split_alignment() returns lim->zone_write_granularity if it is non-zero
and bio_split_io_at() may split a bio with as per bio_split_alignment().
This can real to the write getting rejected by the host drive, as the write
is not aligned to the physical block size.

zonefs also takes its block size from bdev_zone_write_granularity(), so it
would incorrectly use 512 on a disk that requires 4096.

sd_zbc_read_zones() sets the limit from the physical block size for the
same reason. NVMe ZNS and null_blk leave it unset, but the fallback
gives the right answer for them, as their write granularity is the
logical block size. virtio carries a separate value that may exceed it.

Set the zone write granularity from the value that the device reports.

Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://patch.msgid.link/20260918140641.2031075-2-cassel@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 264 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
new file mode 100644
index 000000000..888b06731
--- /dev/null
+++ b/drivers/clocksource/timer-atmel-pit.c
@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * at91sam926x_time.c - Periodic Interval Timer (PIT) for at91sam926x
+ *
+ * Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France
+ * Revision	 2005 M. Nicolas Diremdjian, ATMEL Rousset, France
+ * Converted to ClockSource/ClockEvents by David Brownell.
+ */
+
+#define pr_fmt(fmt)	"AT91: PIT: " fmt
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+#define AT91_PIT_MR		0x00			/* Mode Register */
+#define AT91_PIT_PITIEN			BIT(25)			/* Timer Interrupt Enable */
+#define AT91_PIT_PITEN			BIT(24)			/* Timer Enabled */
+#define AT91_PIT_PIV			GENMASK(19, 0)		/* Periodic Interval Value */
+
+#define AT91_PIT_SR		0x04			/* Status Register */
+#define AT91_PIT_PITS			BIT(0)			/* Timer Status */
+
+#define AT91_PIT_PIVR		0x08			/* Periodic Interval Value Register */
+#define AT91_PIT_PIIR		0x0c			/* Periodic Interval Image Register */
+#define AT91_PIT_PICNT			GENMASK(31, 20)		/* Interval Counter */
+#define AT91_PIT_CPIV			GENMASK(19, 0)		/* Inverval Value */
+
+#define PIT_CPIV(x)	((x) & AT91_PIT_CPIV)
+#define PIT_PICNT(x)	(((x) & AT91_PIT_PICNT) >> 20)
+
+struct pit_data {
+	struct clock_event_device	clkevt;
+	struct clocksource		clksrc;
+
+	void __iomem	*base;
+	u32		cycle;
+	u32		cnt;
+	unsigned int	irq;
+	struct clk	*mck;
+};
+
+static inline struct pit_data *clksrc_to_pit_data(struct clocksource *clksrc)
+{
+	return container_of(clksrc, struct pit_data, clksrc);
+}
+
+static inline struct pit_data *clkevt_to_pit_data(struct clock_event_device *clkevt)
+{
+	return container_of(clkevt, struct pit_data, clkevt);
+}
+
+static inline unsigned int pit_read(void __iomem *base, unsigned int reg_offset)
+{
+	return readl_relaxed(base + reg_offset);
+}
+
+static inline void pit_write(void __iomem *base, unsigned int reg_offset, unsigned long value)
+{
+	writel_relaxed(value, base + reg_offset);
+}
+
+/*
+ * Clocksource:  just a monotonic counter of MCK/16 cycles.
+ * We don't care whether or not PIT irqs are enabled.
+ */
+static u64 read_pit_clk(struct clocksource *cs)
+{
+	struct pit_data *data = clksrc_to_pit_data(cs);
+	unsigned long flags;
+	u32 elapsed;
+	u32 t;
+
+	raw_local_irq_save(flags);
+	elapsed = data->cnt;
+	t = pit_read(data->base, AT91_PIT_PIIR);
+	raw_local_irq_restore(flags);
+
+	elapsed += PIT_PICNT(t) * data->cycle;
+	elapsed += PIT_CPIV(t);
+	return elapsed;
+}
+
+static int pit_clkevt_shutdown(struct clock_event_device *dev)
+{
+	struct pit_data *data = clkevt_to_pit_data(dev);
+
+	/* disable irq, leaving the clocksource active */
+	pit_write(data->base, AT91_PIT_MR, (data->cycle - 1) | AT91_PIT_PITEN);
+	return 0;
+}
+
+/*
+ * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
+ */
+static int pit_clkevt_set_periodic(struct clock_event_device *dev)
+{
+	struct pit_data *data = clkevt_to_pit_data(dev);
+
+	/* update clocksource counter */
+	data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
+	pit_write(data->base, AT91_PIT_MR,
+		  (data->cycle - 1) | AT91_PIT_PITEN | AT91_PIT_PITIEN);
+	return 0;
+}
+
+static void at91sam926x_pit_suspend(struct clock_event_device *cedev)
+{
+	struct pit_data *data = clkevt_to_pit_data(cedev);
+
+	/* Disable timer */
+	pit_write(data->base, AT91_PIT_MR, 0);
+}
+
+static void at91sam926x_pit_reset(struct pit_data *data)
+{
+	/* Disable timer and irqs */
+	pit_write(data->base, AT91_PIT_MR, 0);
+
+	/* Clear any pending interrupts, wait for PIT to stop counting */
+	while (PIT_CPIV(pit_read(data->base, AT91_PIT_PIVR)) != 0)
+		cpu_relax();
+
+	/* Start PIT but don't enable IRQ */
+	pit_write(data->base, AT91_PIT_MR,
+		  (data->cycle - 1) | AT91_PIT_PITEN);
+}
+
+static void at91sam926x_pit_resume(struct clock_event_device *cedev)
+{
+	struct pit_data *data = clkevt_to_pit_data(cedev);
+
+	at91sam926x_pit_reset(data);
+}
+
+/*
+ * IRQ handler for the timer.
+ */
+static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id)
+{
+	struct pit_data *data = dev_id;
+
+	/* The PIT interrupt may be disabled, and is shared */
+	if (clockevent_state_periodic(&data->clkevt) &&
+	    (pit_read(data->base, AT91_PIT_SR) & AT91_PIT_PITS)) {
+		/* Get number of ticks performed before irq, and ack it */
+		data->cnt += data->cycle * PIT_PICNT(pit_read(data->base,
+							      AT91_PIT_PIVR));
+		data->clkevt.event_handler(&data->clkevt);
+
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+/*
+ * Set up both clocksource and clockevent support.
+ */
+static int __init at91sam926x_pit_dt_init(struct device_node *node)
+{
+	unsigned long   pit_rate;
+	unsigned        bits;
+	int             ret;
+	struct pit_data *data;
+
+	data = kzalloc_obj(*data);
+	if (!data)
+		return -ENOMEM;
+
+	data->base = of_iomap(node, 0);
+	if (!data->base) {
+		pr_err("Could not map PIT address\n");
+		ret = -ENXIO;
+		goto exit;
+	}
+
+	data->mck = of_clk_get(node, 0);
+	if (IS_ERR(data->mck)) {
+		pr_err("Unable to get mck clk\n");
+		ret = PTR_ERR(data->mck);
+		goto exit;
+	}
+
+	ret = clk_prepare_enable(data->mck);
+	if (ret) {
+		pr_err("Unable to enable mck\n");
+		goto exit;
+	}
+
+	/* Get the interrupts property */
+	data->irq = irq_of_parse_and_map(node, 0);
+	if (!data->irq) {
+		pr_err("Unable to get IRQ from DT\n");
+		ret = -EINVAL;
+		goto exit;
+	}
+
+	/*
+	 * Use our actual MCK to figure out how many MCK/16 ticks per
+	 * 1/HZ period (instead of a compile-time constant LATCH).
+	 */
+	pit_rate = clk_get_rate(data->mck) / 16;
+	data->cycle = DIV_ROUND_CLOSEST(pit_rate, HZ);
+	WARN_ON(((data->cycle - 1) & ~AT91_PIT_PIV) != 0);
+
+	/* Initialize and enable the timer */
+	at91sam926x_pit_reset(data);
+
+	/*
+	 * Register clocksource.  The high order bits of PIV are unused,
+	 * so this isn't a 32-bit counter unless we get clockevent irqs.
+	 */
+	bits = 12 /* PICNT */ + ilog2(data->cycle) /* PIV */;
+	data->clksrc.mask = CLOCKSOURCE_MASK(bits);
+	data->clksrc.name = "pit";
+	data->clksrc.rating = 175;
+	data->clksrc.read = read_pit_clk;
+	data->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+	
+	ret = clocksource_register_hz(&data->clksrc, pit_rate);
+	if (ret) {
+		pr_err("Failed to register clocksource\n");
+		goto exit;
+	}
+
+	/* Set up irq handler */
+	ret = request_irq(data->irq, at91sam926x_pit_interrupt,
+			  IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
+			  "at91_tick", data);
+	if (ret) {
+		pr_err("Unable to setup IRQ\n");
+		clocksource_unregister(&data->clksrc);
+		goto exit;
+	}
+
+	/* Set up and register clockevents */
+	data->clkevt.name = "pit";
+	data->clkevt.features = CLOCK_EVT_FEAT_PERIODIC;
+	data->clkevt.shift = 32;
+	data->clkevt.mult = div_sc(pit_rate, NSEC_PER_SEC, data->clkevt.shift);
+	data->clkevt.rating = 100;
+	data->clkevt.cpumask = cpumask_of(0);
+
+	data->clkevt.set_state_shutdown = pit_clkevt_shutdown;
+	data->clkevt.set_state_periodic = pit_clkevt_set_periodic;
+	data->clkevt.resume = at91sam926x_pit_resume;
+	data->clkevt.suspend = at91sam926x_pit_suspend;
+	clockevents_register_device(&data->clkevt);
+
+	return 0;
+
+exit:
+	kfree(data);
+	return ret;
+}
+TIMER_OF_DECLARE(at91sam926x_pit, "atmel,at91sam9260-pit",
+		       at91sam926x_pit_dt_init);