Re: [kvm-unit-tests PATCH v8 12/14] x86: intel-iommu: add dmar test

[Alexander Gordeev <agordeev@redhat.com>]

On Mon, Dec 12, 2016 at 11:08:18AM +0800, Peter Xu wrote:
> DMAR test is based on QEMU edu device. A 4B DMA memory copy is carried
> out as the simplest DMAR test.

Hi Peter,

Sorry for missing to provide feedback on your series.
I did just a cursory review, but did not notice few issue below.

> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  lib/pci.h             |   5 ++
>  lib/x86/intel-iommu.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/x86/intel-iommu.h |   4 ++
>  x86/Makefile.common   |   1 +
>  x86/intel-iommu.c     |  51 +++++++++++++++++++
>  5 files changed, 194 insertions(+)
> 
> diff --git a/lib/pci.h b/lib/pci.h
> index d3052ef..26968b1 100644
> --- a/lib/pci.h
> +++ b/lib/pci.h
> @@ -18,6 +18,9 @@ enum {
>  #define PCI_BAR_NUM                     6
>  #define PCI_DEVFN_MAX                   256
>  
> +#define PCI_BDF_GET_DEVFN(x)            ((x) & 0xff)
> +#define PCI_BDF_GET_BUS(x)              (((x) >> 8) & 0xff)
> +
>  struct pci_dev {
>  	uint16_t bdf;
>  	phys_addr_t resource[PCI_BAR_NUM];
> @@ -28,6 +31,8 @@ extern void pci_scan_bars(struct pci_dev *dev);
>  extern void pci_cmd_set_clr(struct pci_dev *dev, uint16_t set, uint16_t clr);
>  extern void pci_enable_defaults(struct pci_dev *dev);
>  
> +typedef phys_addr_t iova_t;
> +
>  extern bool pci_probe(void);
>  extern void pci_print(void);
>  extern bool pci_dev_exists(pcidevaddr_t dev);
> diff --git a/lib/x86/intel-iommu.c b/lib/x86/intel-iommu.c
> index 1887998..86b1805 100644
> --- a/lib/x86/intel-iommu.c
> +++ b/lib/x86/intel-iommu.c
> @@ -11,6 +11,42 @@
>   */
>  
>  #include "intel-iommu.h"
> +#include "libcflat.h"
> +
> +/*
> + * VT-d in QEMU currently only support 39 bits address width, which is
> + * 3-level translation.
> + */
> +#define VTD_PAGE_LEVEL      3
> +#define VTD_CE_AW_39BIT     0x1
> +
> +typedef uint64_t vtd_pte_t;
> +
> +struct vtd_root_entry {
> +	/* Quad 1 */
> +	uint64_t present:1;
> +	uint64_t __reserved:11;
> +	uint64_t context_table_p:52;
> +	/* Quad 2 */
> +	uint64_t __reserved_2;
> +} __attribute__ ((packed));
> +typedef struct vtd_root_entry vtd_re_t;
> +
> +struct vtd_context_entry {
> +	/* Quad 1 */
> +	uint64_t present:1;
> +	uint64_t disable_fault_report:1;
> +	uint64_t trans_type:2;
> +	uint64_t __reserved:8;
> +	uint64_t slptptr:52;
> +	/* Quad 2 */
> +	uint64_t addr_width:3;
> +	uint64_t __ignore:4;
> +	uint64_t __reserved_2:1;
> +	uint64_t domain_id:16;
> +	uint64_t __reserved_3:40;
> +} __attribute__ ((packed));
> +typedef struct vtd_context_entry vtd_ce_t;
>  
>  #define VTD_RTA_MASK  (PAGE_MASK)
>  #define VTD_IRTA_MASK (PAGE_MASK)
> @@ -83,6 +119,103 @@ static void vtd_setup_ir_table(void)
>  	printf("IR table address: 0x%016lx\n", vtd_ir_table());
>  }
>  
> +static void vtd_install_pte(vtd_pte_t *root, iova_t iova,
> +			    phys_addr_t pa, int level_target)
> +{
> +	int level;
> +	unsigned int offset;
> +	void *page;
> +
> +	for (level = VTD_PAGE_LEVEL; level > level_target; level--) {
> +		offset = PGDIR_OFFSET(iova, level);
> +		if (!(root[offset] & VTD_PTE_RW)) {
> +			page = alloc_page();
> +			memset(page, 0, PAGE_SIZE);
> +			root[offset] = virt_to_phys(page) | VTD_PTE_RW;
> +		}
> +		root = (uint64_t *)(phys_to_virt(root[offset] &
> +						 VTD_PTE_ADDR));
> +	}
> +
> +	offset = PGDIR_OFFSET(iova, level);
> +	root[offset] = pa | VTD_PTE_RW;
> +	if (level != 1) {
> +		/* This is huge page */
> +		root[offset] |= VTD_PTE_HUGE;
> +	}
> +}
> +
> +#define  VTD_PHYS_TO_VIRT(x) \
> +	((void *)(((uint64_t)phys_to_virt(x)) >> VTD_PAGE_SHIFT))

I would say this macro is rather superfluous.

> +/**
> + * vtd_map_range: setup IO address mapping for specific memory range
> + *
> + * @sid: source ID of the device to setup
> + * @iova: start IO virtual address
> + * @pa: start physical address
> + * @size: size of the mapping area
> + */
> +void vtd_map_range(uint16_t sid, iova_t iova, phys_addr_t pa, size_t size)
> +{
> +	uint8_t bus_n, devfn;
> +	void *slptptr;
> +	vtd_ce_t *ce;
> +	vtd_re_t *re = phys_to_virt(vtd_root_table());
> +
> +	assert(IS_ALIGNED(iova, SZ_4K));
> +	assert(IS_ALIGNED(pa, SZ_4K));
> +	assert(IS_ALIGNED(size, SZ_4K));
> +
> +	bus_n = PCI_BDF_GET_BUS(sid);
> +	devfn = PCI_BDF_GET_DEVFN(sid);
> +
> +	/* Point to the correct root entry */
> +	re += bus_n;
> +
> +	if (!re->present) {
> +		ce = alloc_page();
> +		memset(ce, 0, PAGE_SIZE);
> +		memset(re, 0, sizeof(*re));
> +		re->context_table_p = virt_to_phys(ce) >> VTD_PAGE_SHIFT;
> +		re->present = 1;
> +		printf("allocated vt-d root entry for PCI bus %d\n",
> +		       bus_n);
> +	} else
> +		ce = VTD_PHYS_TO_VIRT(re->context_table_p);

Seems, it should be instead something like:

		ce = phys_to_virt(re->context_table_p << VTD_PAGE_SHIFT);

> +
> +	/* Point to the correct context entry */
> +	ce += devfn;
> +
> +	if (!ce->present) {
> +		slptptr = alloc_page();
> +		memset(slptptr, 0, PAGE_SIZE);
> +		memset(ce, 0, sizeof(*ce));
> +		/* To make it simple, domain ID is the same as SID */
> +		ce->domain_id = sid;
> +		/* We only test 39 bits width case (3-level paging) */
> +		ce->addr_width = VTD_CE_AW_39BIT;
> +		ce->slptptr = virt_to_phys(slptptr) >> VTD_PAGE_SHIFT;
> +		ce->trans_type = VTD_CONTEXT_TT_MULTI_LEVEL;
> +		ce->present = 1;
> +		/* No error reporting yet */
> +		ce->disable_fault_report = 1;
> +		printf("allocated vt-d context entry for devfn 0x%x\n",
> +		       devfn);
> +	} else
> +		slptptr = VTD_PHYS_TO_VIRT(ce->slptptr);

		slptptr = phys_to_virt(ce->slptptr << VTD_PAGE_SHIFT);

> +	while (size) {
> +		/* TODO: currently we only map 4K pages (level = 1) */
> +		printf("map 4K page IOVA 0x%lx to 0x%lx (sid=0x%04x)\n",
> +		       iova, pa, sid);
> +		vtd_install_pte(slptptr, iova, pa, 1);
> +		size -= VTD_PAGE_SIZE;
> +		iova += VTD_PAGE_SIZE;
> +		pa += VTD_PAGE_SIZE;
> +	}
> +}
> +
>  void vtd_init(void)
>  {
>  	setup_vm();
> diff --git a/lib/x86/intel-iommu.h b/lib/x86/intel-iommu.h
> index 92cc85f..50f67f1 100644
> --- a/lib/x86/intel-iommu.h
> +++ b/lib/x86/intel-iommu.h
> @@ -20,9 +20,12 @@
>  #include "isr.h"
>  #include "smp.h"
>  #include "desc.h"
> +#include "pci.h"
>  #include "asm/io.h"
>  
>  #define Q35_HOST_BRIDGE_IOMMU_ADDR  0xfed90000ULL
> +#define VTD_PAGE_SHIFT              PAGE_SHIFT
> +#define VTD_PAGE_SIZE               PAGE_SIZE
>  
>  /*
>   * Intel IOMMU register specification
> @@ -137,5 +140,6 @@ static inline uint64_t vtd_readq(unsigned int reg)
>  }
>  
>  void vtd_init(void);
> +void vtd_map_range(uint16_t sid, phys_addr_t iova, phys_addr_t pa, size_t size);
>  
>  #endif
> diff --git a/x86/Makefile.common b/x86/Makefile.common
> index 356d879..1dad18b 100644
> --- a/x86/Makefile.common
> +++ b/x86/Makefile.common
> @@ -3,6 +3,7 @@
>  all: test_cases
>  
>  cflatobjs += lib/pci.o
> +cflatobjs += lib/pci-edu.o
>  cflatobjs += lib/x86/io.o
>  cflatobjs += lib/x86/smp.o
>  cflatobjs += lib/x86/vm.o
> diff --git a/x86/intel-iommu.c b/x86/intel-iommu.c
> index f247913..21fd57f 100644
> --- a/x86/intel-iommu.c
> +++ b/x86/intel-iommu.c
> @@ -11,9 +11,50 @@
>   */
>  
>  #include "intel-iommu.h"
> +#include "pci-edu.h"
> +
> +#define VTD_TEST_DMAR_4B ("DMAR 4B memcpy test")
> +
> +void vtd_test_dmar(struct pci_edu_dev *dev)
> +{
> +	void *page = alloc_page();
> +
> +#define DMA_TEST_WORD (0x12345678)
> +	/* Modify the first 4 bytes of the page */
> +	*(uint32_t *)page = DMA_TEST_WORD;
> +
> +	/*
> +	 * Map the newly allocated page into IOVA address 0 (size 4K)
> +	 * of the device address space. Root entry and context entry
> +	 * will be automatically created when needed.
> +	 */
> +	vtd_map_range(dev->pci_dev.bdf, 0, virt_to_phys(page), PAGE_SIZE);
> +
> +	/*
> +	 * DMA the first 4 bytes of the page to EDU device buffer
> +	 * offset 0.
> +	 */
> +	edu_dma(dev, 0, 4, 0, false);
> +
> +	/*
> +	 * DMA the first 4 bytes of EDU device buffer into the page
> +	 * with offset 4 (so it'll be using 4-7 bytes).
> +	 */
> +	edu_dma(dev, 4, 4, 0, true);
> +
> +	/*
> +	 * Check data match between 0-3 bytes and 4-7 bytes of the
> +	 * page.
> +	 */
> +	report(VTD_TEST_DMAR_4B, *((uint32_t *)page + 1) == DMA_TEST_WORD);
> +
> +	free_page(page);
> +}
>  
>  int main(int argc, char *argv[])
>  {
> +	struct pci_edu_dev dev;
> +
>  	vtd_init();
>  
>  	report("fault status check", vtd_readl(DMAR_FSTS_REG) == 0);
> @@ -22,6 +63,16 @@ int main(int argc, char *argv[])
>  	report("IR table setup", vtd_readl(DMAR_GSTS_REG) & VTD_GCMD_IR_TABLE);
>  	report("DMAR enablement", vtd_readl(DMAR_GSTS_REG) & VTD_GCMD_DMAR);
>  	report("IR enablement", vtd_readl(DMAR_GSTS_REG) & VTD_GCMD_IR);
> +	report("DMAR support 39 bits address width",
> +	       vtd_readq(DMAR_CAP_REG) & VTD_CAP_SAGAW);
> +	report("DMAR support huge pages", vtd_readq(DMAR_CAP_REG) & VTD_CAP_SLLPS);
> +
> +	if (!edu_init(&dev)) {
> +		printf("Please specify \"-device edu\" to do "
> +		       "further IOMMU tests.\n");
> +		report_skip(VTD_TEST_DMAR_4B);
> +	} else
> +		vtd_test_dmar(&dev);
>  
>  	return report_summary();
>  }
> -- 
> 2.7.4
>