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bhyve: Fix NVMe BAR size calculation

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The NVMe specification defines bits 13:4 of BAR0 as Reserved (i.e. 0x0).
Most drivers do not enforce this, but the Windows NVMe driver does and
will refuse to start the device (i.e. error 10) if any of these bits are
set.

The current BAR size calculation tries to minimize the amount of memory
the device reserves by scaling the BAR size by the maximum number of
queues supported by the device. But unless the device supports a large
number of queue pairs (over 1536), it will reserve too little memory.

The fix is to allocate a minimum of 16K bytes for BAR0.

Tested on Windows Server 2016 and 2019

Reviewed by:	imp (mentor), araujo, jhb, bhyve
Approved by:	imp (mentor), bhyve (jhb)
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D19676
This commit is contained in:
Chuck Tuffli 2019-04-05 16:54:16 +00:00
parent 4ae3f5a7fd
commit fe1b713e2c
1 changed files with 12 additions and 2 deletions
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14
usr.sbin/bhyve/pci_nvme.c
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@ -85,6 +85,9 @@ static int nvme_debug = 0;
#define NVME_IOSLOTS 8
/* The NVMe spec defines bits 13:4 in BAR0 as reserved */
#define NVME_MMIO_SPACE_MIN (1 << 14)
#define NVME_QUEUES 16
#define NVME_MAX_QENTRIES 2048
@ -1847,9 +1850,16 @@ pci_nvme_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
pci_set_cfgdata8(pi, PCIR_PROGIF,
PCIP_STORAGE_NVM_ENTERPRISE_NVMHCI_1_0);
/* allocate size of nvme registers + doorbell space for all queues */
/*
* Allocate size of NVMe registers + doorbell space for all queues.
*
* The specification requires a minimum memory I/O window size of 16K.
* The Windows driver will refuse to start a device with a smaller
* window.
*/
pci_membar_sz = sizeof(struct nvme_registers) +
2*sizeof(uint32_t)*(sc->max_queues + 1);
2 * sizeof(uint32_t) * (sc->max_queues + 1);
pci_membar_sz = MAX(pci_membar_sz, NVME_MMIO_SPACE_MIN);
DPRINTF(("nvme membar size: %u\r\n", pci_membar_sz));