On Tue, Jul 16, 2019 at 04:36:34PM +0000, Jan Beulich wrote:
> At the same time restrict its scope to just the single source file
> actually using it, and abstract accesses by introducing a union of
> pointers. (A union of the actual table entries is not used to make it
> impossible to [wrongly, once the 128-bit form gets added] perform
> pointer arithmetic / array accesses on derived types.)
> 
> Also move away from updating the entries piecemeal: Construct a full new
> entry, and write it out.
> 
> Signed-off-by: Jan Beulich <jbeul...@suse.com>

Acked-by: Brian Woods <brian.wo...@amd.com>

> ---
> v3: Switch boolean bitfields to bool.
> v2: name {get,free}_intremap_entry()'s last parameter "index" instead of
>      "offset". Introduce union irte32.
> 
> --- a/xen/drivers/passthrough/amd/iommu_intr.c
> +++ b/xen/drivers/passthrough/amd/iommu_intr.c
> @@ -23,6 +23,28 @@
>   #include <asm/io_apic.h>
>   #include <xen/keyhandler.h>
>   
> +struct irte_basic {
> +    bool remap_en:1;
> +    bool sup_io_pf:1;
> +    unsigned int int_type:3;
> +    bool rq_eoi:1;
> +    bool dm:1;
> +    bool guest_mode:1; /* MBZ */
> +    unsigned int dest:8;
> +    unsigned int vector:8;
> +    unsigned int :8;
> +};
> +
> +union irte32 {
> +    uint32_t raw[1];
> +    struct irte_basic basic;
> +};
> +
> +union irte_ptr {
> +    void *ptr;
> +    union irte32 *ptr32;
> +};
> +
>   #define INTREMAP_TABLE_ORDER    1
>   #define INTREMAP_LENGTH 0xB
>   #define INTREMAP_ENTRIES (1 << INTREMAP_LENGTH)
> @@ -101,47 +123,44 @@ static unsigned int alloc_intremap_entry
>       return slot;
>   }
>   
> -static u32 *get_intremap_entry(int seg, int bdf, int offset)
> +static union irte_ptr get_intremap_entry(unsigned int seg, unsigned int bdf,
> +                                         unsigned int index)
>   {
> -    u32 *table = get_ivrs_mappings(seg)[bdf].intremap_table;
> +    union irte_ptr table = {
> +        .ptr = get_ivrs_mappings(seg)[bdf].intremap_table
> +    };
> +
> +    ASSERT(table.ptr && (index < INTREMAP_ENTRIES));
>   
> -    ASSERT( (table != NULL) && (offset < INTREMAP_ENTRIES) );
> +    table.ptr32 += index;
>   
> -    return table + offset;
> +    return table;
>   }
>   
> -static void free_intremap_entry(int seg, int bdf, int offset)
> -{
> -    u32 *entry = get_intremap_entry(seg, bdf, offset);
> -
> -    memset(entry, 0, sizeof(u32));
> -    __clear_bit(offset, get_ivrs_mappings(seg)[bdf].intremap_inuse);
> -}
> -
> -static void update_intremap_entry(u32* entry, u8 vector, u8 int_type,
> -    u8 dest_mode, u8 dest)
> -{
> -    set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, 0,
> -                            INT_REMAP_ENTRY_REMAPEN_MASK,
> -                            INT_REMAP_ENTRY_REMAPEN_SHIFT, entry);
> -    set_field_in_reg_u32(IOMMU_CONTROL_DISABLED, *entry,
> -                            INT_REMAP_ENTRY_SUPIOPF_MASK,
> -                            INT_REMAP_ENTRY_SUPIOPF_SHIFT, entry);
> -    set_field_in_reg_u32(int_type, *entry,
> -                            INT_REMAP_ENTRY_INTTYPE_MASK,
> -                            INT_REMAP_ENTRY_INTTYPE_SHIFT, entry);
> -    set_field_in_reg_u32(IOMMU_CONTROL_DISABLED, *entry,
> -                            INT_REMAP_ENTRY_REQEOI_MASK,
> -                            INT_REMAP_ENTRY_REQEOI_SHIFT, entry);
> -    set_field_in_reg_u32((u32)dest_mode, *entry,
> -                            INT_REMAP_ENTRY_DM_MASK,
> -                            INT_REMAP_ENTRY_DM_SHIFT, entry);
> -    set_field_in_reg_u32((u32)dest, *entry,
> -                            INT_REMAP_ENTRY_DEST_MAST,
> -                            INT_REMAP_ENTRY_DEST_SHIFT, entry);
> -    set_field_in_reg_u32((u32)vector, *entry,
> -                            INT_REMAP_ENTRY_VECTOR_MASK,
> -                            INT_REMAP_ENTRY_VECTOR_SHIFT, entry);
> +static void free_intremap_entry(unsigned int seg, unsigned int bdf,
> +                                unsigned int index)
> +{
> +    union irte_ptr entry = get_intremap_entry(seg, bdf, index);
> +
> +    ACCESS_ONCE(entry.ptr32->raw[0]) = 0;
> +
> +    __clear_bit(index, get_ivrs_mappings(seg)[bdf].intremap_inuse);
> +}
> +
> +static void update_intremap_entry(union irte_ptr entry, unsigned int vector,
> +                                  unsigned int int_type,
> +                                  unsigned int dest_mode, unsigned int dest)
> +{
> +    struct irte_basic basic = {
> +        .remap_en = true,
> +        .int_type = int_type,
> +        .dm = dest_mode,
> +        .dest = dest,
> +        .vector = vector,
> +    };
> +
> +    ACCESS_ONCE(entry.ptr32->raw[0]) =
> +        container_of(&basic, union irte32, basic)->raw[0];
>   }
>   
>   static inline int get_rte_index(const struct IO_APIC_route_entry *rte)
> @@ -163,7 +182,7 @@ static int update_intremap_entry_from_io
>       u16 *index)
>   {
>       unsigned long flags;
> -    u32* entry;
> +    union irte_ptr entry;
>       u8 delivery_mode, dest, vector, dest_mode;
>       int req_id;
>       spinlock_t *lock;
> @@ -201,12 +220,8 @@ static int update_intremap_entry_from_io
>            * so need to recover vector and delivery mode from IRTE.
>            */
>           ASSERT(get_rte_index(rte) == offset);
> -        vector = get_field_from_reg_u32(*entry,
> -                                        INT_REMAP_ENTRY_VECTOR_MASK,
> -                                        INT_REMAP_ENTRY_VECTOR_SHIFT);
> -        delivery_mode = get_field_from_reg_u32(*entry,
> -                                               INT_REMAP_ENTRY_INTTYPE_MASK,
> -                                               
> INT_REMAP_ENTRY_INTTYPE_SHIFT);
> +        vector = entry.ptr32->basic.vector;
> +        delivery_mode = entry.ptr32->basic.int_type;
>       }
>       update_intremap_entry(entry, vector, delivery_mode, dest_mode, dest);
>   
> @@ -228,7 +243,7 @@ int __init amd_iommu_setup_ioapic_remapp
>   {
>       struct IO_APIC_route_entry rte;
>       unsigned long flags;
> -    u32* entry;
> +    union irte_ptr entry;
>       int apic, pin;
>       u8 delivery_mode, dest, vector, dest_mode;
>       u16 seg, bdf, req_id;
> @@ -407,16 +422,14 @@ unsigned int amd_iommu_read_ioapic_from_
>           u16 bdf = ioapic_sbdf[idx].bdf;
>           u16 seg = ioapic_sbdf[idx].seg;
>           u16 req_id = get_intremap_requestor_id(seg, bdf);
> -        const u32 *entry = get_intremap_entry(seg, req_id, offset);
> +        union irte_ptr entry = get_intremap_entry(seg, req_id, offset);
>   
>           ASSERT(offset == (val & (INTREMAP_ENTRIES - 1)));
>           val &= ~(INTREMAP_ENTRIES - 1);
> -        val |= get_field_from_reg_u32(*entry,
> -                                      INT_REMAP_ENTRY_INTTYPE_MASK,
> -                                      INT_REMAP_ENTRY_INTTYPE_SHIFT) << 8;
> -        val |= get_field_from_reg_u32(*entry,
> -                                      INT_REMAP_ENTRY_VECTOR_MASK,
> -                                      INT_REMAP_ENTRY_VECTOR_SHIFT);
> +        val |= MASK_INSR(entry.ptr32->basic.int_type,
> +                         IO_APIC_REDIR_DELIV_MODE_MASK);
> +        val |= MASK_INSR(entry.ptr32->basic.vector,
> +                         IO_APIC_REDIR_VECTOR_MASK);
>       }
>   
>       return val;
> @@ -427,7 +440,7 @@ static int update_intremap_entry_from_ms
>       int *remap_index, const struct msi_msg *msg, u32 *data)
>   {
>       unsigned long flags;
> -    u32* entry;
> +    union irte_ptr entry;
>       u16 req_id, alias_id;
>       u8 delivery_mode, dest, vector, dest_mode;
>       spinlock_t *lock;
> @@ -581,7 +594,7 @@ void amd_iommu_read_msi_from_ire(
>       const struct pci_dev *pdev = msi_desc->dev;
>       u16 bdf = pdev ? PCI_BDF2(pdev->bus, pdev->devfn) : hpet_sbdf.bdf;
>       u16 seg = pdev ? pdev->seg : hpet_sbdf.seg;
> -    const u32 *entry;
> +    union irte_ptr entry;
>   
>       if ( IS_ERR_OR_NULL(_find_iommu_for_device(seg, bdf)) )
>           return;
> @@ -597,12 +610,10 @@ void amd_iommu_read_msi_from_ire(
>       }
>   
>       msg->data &= ~(INTREMAP_ENTRIES - 1);
> -    msg->data |= get_field_from_reg_u32(*entry,
> -                                        INT_REMAP_ENTRY_INTTYPE_MASK,
> -                                        INT_REMAP_ENTRY_INTTYPE_SHIFT) << 8;
> -    msg->data |= get_field_from_reg_u32(*entry,
> -                                        INT_REMAP_ENTRY_VECTOR_MASK,
> -                                        INT_REMAP_ENTRY_VECTOR_SHIFT);
> +    msg->data |= MASK_INSR(entry.ptr32->basic.int_type,
> +                           MSI_DATA_DELIVERY_MODE_MASK);
> +    msg->data |= MASK_INSR(entry.ptr32->basic.vector,
> +                           MSI_DATA_VECTOR_MASK);
>   }
>   
>   int __init amd_iommu_free_intremap_table(
> --- a/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h
> +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h
> @@ -469,22 +469,6 @@ struct amd_iommu_pte {
>   #define IOMMU_CONTROL_DISABLED      0
>   #define IOMMU_CONTROL_ENABLED       1
>   
> -/* interrupt remapping table */
> -#define INT_REMAP_ENTRY_REMAPEN_MASK    0x00000001
> -#define INT_REMAP_ENTRY_REMAPEN_SHIFT   0
> -#define INT_REMAP_ENTRY_SUPIOPF_MASK    0x00000002
> -#define INT_REMAP_ENTRY_SUPIOPF_SHIFT   1
> -#define INT_REMAP_ENTRY_INTTYPE_MASK    0x0000001C
> -#define INT_REMAP_ENTRY_INTTYPE_SHIFT   2
> -#define INT_REMAP_ENTRY_REQEOI_MASK     0x00000020
> -#define INT_REMAP_ENTRY_REQEOI_SHIFT    5
> -#define INT_REMAP_ENTRY_DM_MASK         0x00000040
> -#define INT_REMAP_ENTRY_DM_SHIFT        6
> -#define INT_REMAP_ENTRY_DEST_MAST       0x0000FF00
> -#define INT_REMAP_ENTRY_DEST_SHIFT      8
> -#define INT_REMAP_ENTRY_VECTOR_MASK     0x00FF0000
> -#define INT_REMAP_ENTRY_VECTOR_SHIFT    16
> -
>   #define INV_IOMMU_ALL_PAGES_ADDRESS      ((1ULL << 63) - 1)
>   
>   #define IOMMU_RING_BUFFER_PTR_MASK                  0x0007FFF0
> 

-- 
Brian Woods

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