diff mbox

[v5,13/22] KVM: arm64: vgic-its: Check the device id matches TYPER DEVBITS range

Message ID 1492164934-988-14-git-send-email-eric.auger@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger April 14, 2017, 10:15 a.m. UTC
On MAPD we currently check the device id can be stored in the device table.
Let's first check it can be encoded within the range defined by TYPER
DEVBITS.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v4 -> v5:
- use GIC_ENCODE_SZ macro

v3 -> v4:
- VITS_TYPER_DEVBITS set to 16 for homogeneity
- use BIT_ULL
---
 virt/kvm/arm/vgic/vgic-its.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Prakash B April 26, 2017, 11:29 a.m. UTC | #1
On Fri, Apr 14, 2017 at 3:45 PM, Eric Auger <eric.auger@redhat.com> wrote:
> On MAPD we currently check the device id can be stored in the device table.
> Let's first check it can be encoded within the range defined by TYPER
> DEVBITS.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Prakash, Brahmajyosyula <Brahmajyosyula.Prakash@cavium.com>
Christoffer Dall April 27, 2017, 4:48 p.m. UTC | #2
On Fri, Apr 14, 2017 at 12:15:25PM +0200, Eric Auger wrote:
> On MAPD we currently check the device id can be stored in the device table.
> Let's first check it can be encoded within the range defined by TYPER
> DEVBITS.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> 
> ---
> 
> v4 -> v5:
> - use GIC_ENCODE_SZ macro
> 
> v3 -> v4:
> - VITS_TYPER_DEVBITS set to 16 for homogeneity
> - use BIT_ULL
> ---
>  virt/kvm/arm/vgic/vgic-its.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 757598d..de1ed6d 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -194,6 +194,7 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
>  #define GIC_LPI_OFFSET 8192
>  
>  #define VITS_TYPER_IDBITS 16
> +#define VITS_TYPER_DEVBITS 16
>  
>  /*
>   * Finds and returns a collection in the ITS collection table.
> @@ -394,7 +395,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
>  	 * To avoid memory waste in the guest, we keep the number of IDBits and
>  	 * DevBits low - as least for the time being.
>  	 */
> -	reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
> +	reg |= GIC_ENCODE_SZ(VITS_TYPER_DEVBITS, 5) << GITS_TYPER_DEVBITS_SHIFT;
>  	reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
>  	reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
>  
> @@ -639,10 +640,10 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
>   * Check whether an ID can be stored into the corresponding guest table.
>   * For a direct table this is pretty easy, but gets a bit nasty for
>   * indirect tables. We check whether the resulting guest physical address
> - * is actually valid (covered by a memslot and guest accessbible).
> + * is actually valid (covered by a memslot and guest accessible).
>   * For this we have to read the respective first level entry.
>   */
> -static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
> +static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id)
>  {
>  	int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
>  	int index;
> @@ -650,6 +651,9 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
>  	gfn_t gfn;
>  	int esz = GITS_BASER_ENTRY_SIZE(baser);
>  
> +	if (id >= BIT_ULL(VITS_TYPER_DEVBITS))
> +		return false;
> +

Isn't vgic_its_check_id called with both a device id and a collection
id?  How can this then be a valid check?

>  	if (!(baser & GITS_BASER_INDIRECT)) {
>  		phys_addr_t addr;
>  
> -- 
> 2.5.5
> 

Thanks,
-Christoffer
Eric Auger April 27, 2017, 5:24 p.m. UTC | #3
Hi,

On 27/04/2017 18:48, Christoffer Dall wrote:
> On Fri, Apr 14, 2017 at 12:15:25PM +0200, Eric Auger wrote:
>> On MAPD we currently check the device id can be stored in the device table.
>> Let's first check it can be encoded within the range defined by TYPER
>> DEVBITS.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>>
>> v4 -> v5:
>> - use GIC_ENCODE_SZ macro
>>
>> v3 -> v4:
>> - VITS_TYPER_DEVBITS set to 16 for homogeneity
>> - use BIT_ULL
>> ---
>>  virt/kvm/arm/vgic/vgic-its.c | 10 +++++++---
>>  1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
>> index 757598d..de1ed6d 100644
>> --- a/virt/kvm/arm/vgic/vgic-its.c
>> +++ b/virt/kvm/arm/vgic/vgic-its.c
>> @@ -194,6 +194,7 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
>>  #define GIC_LPI_OFFSET 8192
>>  
>>  #define VITS_TYPER_IDBITS 16
>> +#define VITS_TYPER_DEVBITS 16
>>  
>>  /*
>>   * Finds and returns a collection in the ITS collection table.
>> @@ -394,7 +395,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
>>  	 * To avoid memory waste in the guest, we keep the number of IDBits and
>>  	 * DevBits low - as least for the time being.
>>  	 */
>> -	reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
>> +	reg |= GIC_ENCODE_SZ(VITS_TYPER_DEVBITS, 5) << GITS_TYPER_DEVBITS_SHIFT;
>>  	reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
>>  	reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
>>  
>> @@ -639,10 +640,10 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
>>   * Check whether an ID can be stored into the corresponding guest table.
>>   * For a direct table this is pretty easy, but gets a bit nasty for
>>   * indirect tables. We check whether the resulting guest physical address
>> - * is actually valid (covered by a memslot and guest accessbible).
>> + * is actually valid (covered by a memslot and guest accessible).
>>   * For this we have to read the respective first level entry.
>>   */
>> -static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
>> +static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id)
>>  {
>>  	int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
>>  	int index;
>> @@ -650,6 +651,9 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
>>  	gfn_t gfn;
>>  	int esz = GITS_BASER_ENTRY_SIZE(baser);
>>  
>> +	if (id >= BIT_ULL(VITS_TYPER_DEVBITS))
>> +		return false;
>> +
> 
> Isn't vgic_its_check_id called with both a device id and a collection
> id?  How can this then be a valid check?

Hum yes that's correct. In practice the test is correct for collection
ID too since our virtual implementation supports collections in memory
(GITS_TYPER.CIL ==0, spec 8.19.8) and a 16-bit collection ID is
supported. But this is by chance and this really deserves some proper
differentiation. Thank you for spotting that one too!

Thanks

Eric
> 
>>  	if (!(baser & GITS_BASER_INDIRECT)) {
>>  		phys_addr_t addr;
>>  
>> -- 
>> 2.5.5
>>
> 
> Thanks,
> -Christoffer
>
diff mbox

Patch

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 757598d..de1ed6d 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -194,6 +194,7 @@  static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
 #define GIC_LPI_OFFSET 8192
 
 #define VITS_TYPER_IDBITS 16
+#define VITS_TYPER_DEVBITS 16
 
 /*
  * Finds and returns a collection in the ITS collection table.
@@ -394,7 +395,7 @@  static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
 	 * To avoid memory waste in the guest, we keep the number of IDBits and
 	 * DevBits low - as least for the time being.
 	 */
-	reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
+	reg |= GIC_ENCODE_SZ(VITS_TYPER_DEVBITS, 5) << GITS_TYPER_DEVBITS_SHIFT;
 	reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
 	reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
 
@@ -639,10 +640,10 @@  static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
  * Check whether an ID can be stored into the corresponding guest table.
  * For a direct table this is pretty easy, but gets a bit nasty for
  * indirect tables. We check whether the resulting guest physical address
- * is actually valid (covered by a memslot and guest accessbible).
+ * is actually valid (covered by a memslot and guest accessible).
  * For this we have to read the respective first level entry.
  */
-static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
+static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id)
 {
 	int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
 	int index;
@@ -650,6 +651,9 @@  static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
 	gfn_t gfn;
 	int esz = GITS_BASER_ENTRY_SIZE(baser);
 
+	if (id >= BIT_ULL(VITS_TYPER_DEVBITS))
+		return false;
+
 	if (!(baser & GITS_BASER_INDIRECT)) {
 		phys_addr_t addr;