When Shared Virtual Memory is exposed to a guest via vIOMMU, scalable
IOTLB invalidation may be passed down from outside IOMMU subsystems.
This patch adds invalidation functions that can be used for additional
translation cache types.
Signed-off-by: Jacob Pan <[email protected]>
---
drivers/iommu/dmar.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/intel-iommu.h | 21 +++++++++++++++----
2 files changed, 67 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 6d969a1..0cda6fb 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -1357,6 +1357,21 @@ void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
qi_submit_sync(&desc, iommu);
}
+/* PASID-based IOTLB Invalidate */
+void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u64 addr, u32 pasid,
+ unsigned int size_order, u64 granu, int ih)
+{
+ struct qi_desc desc;
+
+ desc.qw0 = QI_EIOTLB_PASID(pasid) | QI_EIOTLB_DID(did) |
+ QI_EIOTLB_GRAN(granu) | QI_EIOTLB_TYPE;
+ desc.qw1 = QI_EIOTLB_ADDR(addr) | QI_EIOTLB_IH(ih) |
+ QI_EIOTLB_AM(size_order);
+ desc.qw2 = 0;
+ desc.qw3 = 0;
+ qi_submit_sync(&desc, iommu);
+}
+
void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
u16 qdep, u64 addr, unsigned mask)
{
@@ -1380,6 +1395,41 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
qi_submit_sync(&desc, iommu);
}
+/* PASID-based device IOTLB Invalidate */
+void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
+ u32 pasid, u16 qdep, u64 addr, unsigned size, u64 granu)
+{
+ struct qi_desc desc;
+
+ desc.qw0 = QI_DEV_EIOTLB_PASID(pasid) | QI_DEV_EIOTLB_SID(sid) |
+ QI_DEV_EIOTLB_QDEP(qdep) | QI_DEIOTLB_TYPE |
+ QI_DEV_IOTLB_PFSID(pfsid);
+ desc.qw1 = QI_DEV_EIOTLB_GLOB(granu);
+
+ /* If S bit is 0, we only flush a single page. If S bit is set,
+ * The least significant zero bit indicates the size. VT-d spec
+ * 6.5.2.6
+ */
+ if (!size)
+ desc.qw0 |= QI_DEV_EIOTLB_ADDR(addr) & ~QI_DEV_EIOTLB_SIZE;
+ else {
+ unsigned long mask = 1UL << (VTD_PAGE_SHIFT + size);
+
+ desc.qw1 |= QI_DEV_EIOTLB_ADDR(addr & ~mask) | QI_DEV_EIOTLB_SIZE;
+ }
+ qi_submit_sync(&desc, iommu);
+}
+
+void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64 granu, int pasid)
+{
+ struct qi_desc desc;
+
+ desc.qw0 = QI_PC_TYPE | QI_PC_DID(did) | QI_PC_GRAN(granu) | QI_PC_PASID(pasid);
+ desc.qw1 = 0;
+ desc.qw2 = 0;
+ desc.qw3 = 0;
+ qi_submit_sync(&desc, iommu);
+}
/*
* Disable Queued Invalidation interface.
*/
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 94d3a9a..1cdb35b 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -339,7 +339,7 @@ enum {
#define QI_IOTLB_GRAN(gran) (((u64)gran) >> (DMA_TLB_FLUSH_GRANU_OFFSET-4))
#define QI_IOTLB_ADDR(addr) (((u64)addr) & VTD_PAGE_MASK)
#define QI_IOTLB_IH(ih) (((u64)ih) << 6)
-#define QI_IOTLB_AM(am) (((u8)am))
+#define QI_IOTLB_AM(am) (((u8)am) & 0x3f)
#define QI_CC_FM(fm) (((u64)fm) << 48)
#define QI_CC_SID(sid) (((u64)sid) << 32)
@@ -357,17 +357,22 @@ enum {
#define QI_PC_DID(did) (((u64)did) << 16)
#define QI_PC_GRAN(gran) (((u64)gran) << 4)
-#define QI_PC_ALL_PASIDS (QI_PC_TYPE | QI_PC_GRAN(0))
-#define QI_PC_PASID_SEL (QI_PC_TYPE | QI_PC_GRAN(1))
+/* PASID cache invalidation granu */
+#define QI_PC_ALL_PASIDS 0
+#define QI_PC_PASID_SEL 1
#define QI_EIOTLB_ADDR(addr) ((u64)(addr) & VTD_PAGE_MASK)
#define QI_EIOTLB_GL(gl) (((u64)gl) << 7)
#define QI_EIOTLB_IH(ih) (((u64)ih) << 6)
-#define QI_EIOTLB_AM(am) (((u64)am))
+#define QI_EIOTLB_AM(am) (((u64)am) & 0x3f)
#define QI_EIOTLB_PASID(pasid) (((u64)pasid) << 32)
#define QI_EIOTLB_DID(did) (((u64)did) << 16)
#define QI_EIOTLB_GRAN(gran) (((u64)gran) << 4)
+/* QI Dev-IOTLB inv granu */
+#define QI_DEV_IOTLB_GRAN_ALL 1
+#define QI_DEV_IOTLB_GRAN_PASID_SEL 0
+
#define QI_DEV_EIOTLB_ADDR(a) ((u64)(a) & VTD_PAGE_MASK)
#define QI_DEV_EIOTLB_SIZE (((u64)1) << 11)
#define QI_DEV_EIOTLB_GLOB(g) ((u64)g)
@@ -658,8 +663,16 @@ extern void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid,
u8 fm, u64 type);
extern void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
unsigned int size_order, u64 type);
+extern void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u64 addr,
+ u32 pasid, unsigned int size_order, u64 type, int ih);
extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
u16 qdep, u64 addr, unsigned mask);
+
+extern void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
+ u32 pasid, u16 qdep, u64 addr, unsigned size, u64 granu);
+
+extern void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64 granu, int pasid);
+
extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
extern int dmar_ir_support(void);
--
2.7.4
Hi Jacob,
On 6/9/19 3:44 PM, Jacob Pan wrote:
> When Shared Virtual Memory is exposed to a guest via vIOMMU, scalable
> IOTLB invalidation may be passed down from outside IOMMU subsystems.
> This patch adds invalidation functions that can be used for additional
> translation cache types.
>
> Signed-off-by: Jacob Pan <[email protected]>
> ---
> drivers/iommu/dmar.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/intel-iommu.h | 21 +++++++++++++++----
> 2 files changed, 67 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 6d969a1..0cda6fb 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -1357,6 +1357,21 @@ void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> qi_submit_sync(&desc, iommu);
> }
>
> +/* PASID-based IOTLB Invalidate */
> +void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u64 addr, u32 pasid,
> + unsigned int size_order, u64 granu, int ih)
> +{
> + struct qi_desc desc;
nit: you could also init to {};
> +
> + desc.qw0 = QI_EIOTLB_PASID(pasid) | QI_EIOTLB_DID(did) |
> + QI_EIOTLB_GRAN(granu) | QI_EIOTLB_TYPE;
> + desc.qw1 = QI_EIOTLB_ADDR(addr) | QI_EIOTLB_IH(ih) |
> + QI_EIOTLB_AM(size_order);
> + desc.qw2 = 0;
> + desc.qw3 = 0;
> + qi_submit_sync(&desc, iommu);
> +}
> +
> void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> u16 qdep, u64 addr, unsigned mask)
> {
> @@ -1380,6 +1395,41 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> qi_submit_sync(&desc, iommu);
> }
>
> +/* PASID-based device IOTLB Invalidate */
> +void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> + u32 pasid, u16 qdep, u64 addr, unsigned size, u64 granu)
s/size/size_order
> +{
> + struct qi_desc desc;
> +
> + desc.qw0 = QI_DEV_EIOTLB_PASID(pasid) | QI_DEV_EIOTLB_SID(sid) |
> + QI_DEV_EIOTLB_QDEP(qdep) | QI_DEIOTLB_TYPE |
> + QI_DEV_IOTLB_PFSID(pfsid);
maybe add a comment to remind MIP hint is sent to 0 as of now.
> + desc.qw1 = QI_DEV_EIOTLB_GLOB(granu);
> +
> + /* If S bit is 0, we only flush a single page. If S bit is set,
> + * The least significant zero bit indicates the size. VT-d spec
> + * 6.5.2.6
> + */
> + if (!size)
> + desc.qw0 |= QI_DEV_EIOTLB_ADDR(addr) & ~QI_DEV_EIOTLB_SIZE;
this is qw1.
> + else {
> + unsigned long mask = 1UL << (VTD_PAGE_SHIFT + size);
don't you miss a "- 1 " here?
> +
> + desc.qw1 |= QI_DEV_EIOTLB_ADDR(addr & ~mask) | QI_DEV_EIOTLB_SIZE;
desc.qw1 |= addr & ~mask | QI_DEV_EIOTLB_SIZE;
ie. I don't think QI_DEV_EIOTLB_ADDR is useful here?
So won't the following lines do the job?
unsigned long mask = 1UL << (VTD_PAGE_SHIFT + size) -1;
desc.qw1 |= addr & ~mask;
if (size)
desc.qw1 |= QI_DEV_EIOTLB_SIZE
> + }
> + qi_submit_sync(&desc, iommu);
> +}
> +
> +void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64 granu, int pasid)
> +{
> + struct qi_desc desc;
> +
> + desc.qw0 = QI_PC_TYPE | QI_PC_DID(did) | QI_PC_GRAN(granu) | QI_PC_PASID(pasid);
nit: reorder the fields according to the spec, easier to check if any is
missing.
> + desc.qw1 = 0;
> + desc.qw2 = 0;
> + desc.qw3 = 0;
> + qi_submit_sync(&desc, iommu);
> +}
> /*
> * Disable Queued Invalidation interface.
> */
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 94d3a9a..1cdb35b 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -339,7 +339,7 @@ enum {
> #define QI_IOTLB_GRAN(gran) (((u64)gran) >> (DMA_TLB_FLUSH_GRANU_OFFSET-4))
> #define QI_IOTLB_ADDR(addr) (((u64)addr) & VTD_PAGE_MASK)
> #define QI_IOTLB_IH(ih) (((u64)ih) << 6)
> -#define QI_IOTLB_AM(am) (((u8)am))
> +#define QI_IOTLB_AM(am) (((u8)am) & 0x3f)
>
> #define QI_CC_FM(fm) (((u64)fm) << 48)
> #define QI_CC_SID(sid) (((u64)sid) << 32)
> @@ -357,17 +357,22 @@ enum {
> #define QI_PC_DID(did) (((u64)did) << 16)
> #define QI_PC_GRAN(gran) (((u64)gran) << 4)
>
> -#define QI_PC_ALL_PASIDS (QI_PC_TYPE | QI_PC_GRAN(0))
> -#define QI_PC_PASID_SEL (QI_PC_TYPE | QI_PC_GRAN(1))
> +/* PASID cache invalidation granu */
> +#define QI_PC_ALL_PASIDS 0
> +#define QI_PC_PASID_SEL 1
>
> #define QI_EIOTLB_ADDR(addr) ((u64)(addr) & VTD_PAGE_MASK)
> #define QI_EIOTLB_GL(gl) (((u64)gl) << 7)
> #define QI_EIOTLB_IH(ih) (((u64)ih) << 6)
> -#define QI_EIOTLB_AM(am) (((u64)am))
> +#define QI_EIOTLB_AM(am) (((u64)am) & 0x3f)
> #define QI_EIOTLB_PASID(pasid) (((u64)pasid) << 32)
> #define QI_EIOTLB_DID(did) (((u64)did) << 16)
> #define QI_EIOTLB_GRAN(gran) (((u64)gran) << 4)
>
> +/* QI Dev-IOTLB inv granu */
> +#define QI_DEV_IOTLB_GRAN_ALL 1
> +#define QI_DEV_IOTLB_GRAN_PASID_SEL 0
> +
> #define QI_DEV_EIOTLB_ADDR(a) ((u64)(a) & VTD_PAGE_MASK)
> #define QI_DEV_EIOTLB_SIZE (((u64)1) << 11)
> #define QI_DEV_EIOTLB_GLOB(g) ((u64)g)
> @@ -658,8 +663,16 @@ extern void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid,
> u8 fm, u64 type);
> extern void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> unsigned int size_order, u64 type);
> +extern void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> + u32 pasid, unsigned int size_order, u64 type, int ih);
> extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> u16 qdep, u64 addr, unsigned mask);
> +
> +extern void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> + u32 pasid, u16 qdep, u64 addr, unsigned size, u64 granu);
s/size/size_order
> +
> +extern void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64 granu, int pasid);
> +
> extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
>
> extern int dmar_ir_support(void);
>
Thanks
Eric
On Thu, 18 Jul 2019 10:35:37 +0200
Auger Eric <[email protected]> wrote:
> Hi Jacob,
>
> On 6/9/19 3:44 PM, Jacob Pan wrote:
> > When Shared Virtual Memory is exposed to a guest via vIOMMU,
> > scalable IOTLB invalidation may be passed down from outside IOMMU
> > subsystems. This patch adds invalidation functions that can be used
> > for additional translation cache types.
> >
> > Signed-off-by: Jacob Pan <[email protected]>
> > ---
> > drivers/iommu/dmar.c | 50
> > +++++++++++++++++++++++++++++++++++++++++++++
> > include/linux/intel-iommu.h | 21 +++++++++++++++---- 2 files
> > changed, 67 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> > index 6d969a1..0cda6fb 100644
> > --- a/drivers/iommu/dmar.c
> > +++ b/drivers/iommu/dmar.c
> > @@ -1357,6 +1357,21 @@ void qi_flush_iotlb(struct intel_iommu
> > *iommu, u16 did, u64 addr, qi_submit_sync(&desc, iommu);
> > }
> >
> > +/* PASID-based IOTLB Invalidate */
> > +void qi_flush_piotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> > u32 pasid,
> > + unsigned int size_order, u64 granu, int ih)
> > +{
> > + struct qi_desc desc;
> nit: you could also init to {};
> > +
> > + desc.qw0 = QI_EIOTLB_PASID(pasid) | QI_EIOTLB_DID(did) |
> > + QI_EIOTLB_GRAN(granu) | QI_EIOTLB_TYPE;
> > + desc.qw1 = QI_EIOTLB_ADDR(addr) | QI_EIOTLB_IH(ih) |
> > + QI_EIOTLB_AM(size_order);
> > + desc.qw2 = 0;
> > + desc.qw3 = 0;
> > + qi_submit_sync(&desc, iommu);
> > +}
> > +
> > void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16
> > pfsid, u16 qdep, u64 addr, unsigned mask)
> > {
> > @@ -1380,6 +1395,41 @@ void qi_flush_dev_iotlb(struct intel_iommu
> > *iommu, u16 sid, u16 pfsid, qi_submit_sync(&desc, iommu);
> > }
> >
> > +/* PASID-based device IOTLB Invalidate */
> > +void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16 sid, u16
> > pfsid,
> > + u32 pasid, u16 qdep, u64 addr, unsigned size, u64
> > granu)
> s/size/size_order
> > +{
> > + struct qi_desc desc;
> > +
> > + desc.qw0 = QI_DEV_EIOTLB_PASID(pasid) |
> > QI_DEV_EIOTLB_SID(sid) |
> > + QI_DEV_EIOTLB_QDEP(qdep) | QI_DEIOTLB_TYPE |
> > + QI_DEV_IOTLB_PFSID(pfsid);
> maybe add a comment to remind MIP hint is sent to 0 as of now.
> > + desc.qw1 = QI_DEV_EIOTLB_GLOB(granu);
> > +
> > + /* If S bit is 0, we only flush a single page. If S bit is
> > set,
> > + * The least significant zero bit indicates the size. VT-d
> > spec
> > + * 6.5.2.6
> > + */
> > + if (!size)
> > + desc.qw0 |= QI_DEV_EIOTLB_ADDR(addr) &
> > ~QI_DEV_EIOTLB_SIZE;
> this is qw1.
my mistake.
> > + else {
> > + unsigned long mask = 1UL << (VTD_PAGE_SHIFT +
> > size);
> don't you miss a "- 1 " here?
your are right
> > +
> > + desc.qw1 |= QI_DEV_EIOTLB_ADDR(addr & ~mask) |
> > QI_DEV_EIOTLB_SIZE;
> desc.qw1 |= addr & ~mask | QI_DEV_EIOTLB_SIZE;
> ie. I don't think QI_DEV_EIOTLB_ADDR is useful here?
>
>
> So won't the following lines do the job?
>
> unsigned long mask = 1UL << (VTD_PAGE_SHIFT + size) -1;
> desc.qw1 |= addr & ~mask;
> if (size)
> desc.qw1 |= QI_DEV_EIOTLB_SIZE
that would work too, and simpler. thanks for the suggestion. will
change.
> > + }
> > + qi_submit_sync(&desc, iommu);
> > +}
> > +
> > +void qi_flush_pasid_cache(struct intel_iommu *iommu, u16 did, u64
> > granu, int pasid) +{
> > + struct qi_desc desc;
> > +
> > + desc.qw0 = QI_PC_TYPE | QI_PC_DID(did) | QI_PC_GRAN(granu)
> > | QI_PC_PASID(pasid);
> nit: reorder the fields according to the spec, easier to check if any
> is missing.
sounds good.
> > + desc.qw1 = 0;
> > + desc.qw2 = 0;
> > + desc.qw3 = 0;
> > + qi_submit_sync(&desc, iommu);
> > +}
> > /*
> > * Disable Queued Invalidation interface.
> > */
> > diff --git a/include/linux/intel-iommu.h
> > b/include/linux/intel-iommu.h index 94d3a9a..1cdb35b 100644
> > --- a/include/linux/intel-iommu.h
> > +++ b/include/linux/intel-iommu.h
> > @@ -339,7 +339,7 @@ enum {
> > #define QI_IOTLB_GRAN(gran) (((u64)gran) >>
> > (DMA_TLB_FLUSH_GRANU_OFFSET-4)) #define QI_IOTLB_ADDR(addr)
> > (((u64)addr) & VTD_PAGE_MASK) #define
> > QI_IOTLB_IH(ih) (((u64)ih) << 6) -#define
> > QI_IOTLB_AM(am) (((u8)am)) +#define
> > QI_IOTLB_AM(am) (((u8)am) & 0x3f)
> > #define QI_CC_FM(fm) (((u64)fm) << 48)
> > #define QI_CC_SID(sid) (((u64)sid) << 32)
> > @@ -357,17 +357,22 @@ enum {
> > #define QI_PC_DID(did) (((u64)did) << 16)
> > #define QI_PC_GRAN(gran) (((u64)gran) << 4)
> >
> > -#define QI_PC_ALL_PASIDS (QI_PC_TYPE | QI_PC_GRAN(0))
> > -#define QI_PC_PASID_SEL (QI_PC_TYPE | QI_PC_GRAN(1))
> > +/* PASID cache invalidation granu */
> > +#define QI_PC_ALL_PASIDS 0
> > +#define QI_PC_PASID_SEL 1
> >
> > #define QI_EIOTLB_ADDR(addr) ((u64)(addr) & VTD_PAGE_MASK)
> > #define QI_EIOTLB_GL(gl) (((u64)gl) << 7)
> > #define QI_EIOTLB_IH(ih) (((u64)ih) << 6)
> > -#define QI_EIOTLB_AM(am) (((u64)am))
> > +#define QI_EIOTLB_AM(am) (((u64)am) & 0x3f)
> > #define QI_EIOTLB_PASID(pasid) (((u64)pasid) << 32)
> > #define QI_EIOTLB_DID(did) (((u64)did) << 16)
> > #define QI_EIOTLB_GRAN(gran) (((u64)gran) << 4)
> >
> > +/* QI Dev-IOTLB inv granu */
> > +#define QI_DEV_IOTLB_GRAN_ALL 1
> > +#define QI_DEV_IOTLB_GRAN_PASID_SEL 0
> > +
> > #define QI_DEV_EIOTLB_ADDR(a) ((u64)(a) & VTD_PAGE_MASK)
> > #define QI_DEV_EIOTLB_SIZE (((u64)1) << 11)
> > #define QI_DEV_EIOTLB_GLOB(g) ((u64)g)
> > @@ -658,8 +663,16 @@ extern void qi_flush_context(struct
> > intel_iommu *iommu, u16 did, u16 sid, u8 fm, u64 type);
> > extern void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64
> > addr, unsigned int size_order, u64 type);
> > +extern void qi_flush_piotlb(struct intel_iommu *iommu, u16 did,
> > u64 addr,
> > + u32 pasid, unsigned int size_order, u64
> > type, int ih); extern void qi_flush_dev_iotlb(struct intel_iommu
> > *iommu, u16 sid, u16 pfsid, u16 qdep, u64 addr, unsigned mask);
> > +
> > +extern void qi_flush_dev_piotlb(struct intel_iommu *iommu, u16
> > sid, u16 pfsid,
> > + u32 pasid, u16 qdep, u64 addr, unsigned
> > size, u64 granu);
> s/size/size_order
> > +
> > +extern void qi_flush_pasid_cache(struct intel_iommu *iommu, u16
> > did, u64 granu, int pasid); +
> > extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu
> > *iommu);
> > extern int dmar_ir_support(void);
> >
>
> Thanks
>
> Eric
[Jacob Pan]