* [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size as guest wants @ 2019-01-10 13:00 Pierre Morel 2019-01-10 13:00 ` [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request Pierre Morel 0 siblings, 1 reply; 13+ messages in thread From: Pierre Morel @ 2019-01-10 13:00 UTC (permalink / raw) To: walling Cc: borntraeger, cohuck, rth, david, qemu-s390x, qemu-devel, pasic, thuth Changed the subject (kept only in cover letter) Changed the commit message to specify that the PAL/PBA values are given by the guest through the mpcifc call. Pierre Morel (1): s390x/pci: Set the iommu region size mpcifc request hw/s390x/s390-pci-bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 2.7.4 ^ permalink raw reply [flat|nested] 13+ messages in thread
* [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-10 13:00 [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size as guest wants Pierre Morel @ 2019-01-10 13:00 ` Pierre Morel 2019-01-15 13:59 ` Cornelia Huck ` (2 more replies) 0 siblings, 3 replies; 13+ messages in thread From: Pierre Morel @ 2019-01-10 13:00 UTC (permalink / raw) To: walling Cc: borntraeger, cohuck, rth, david, qemu-s390x, qemu-devel, pasic, thuth The size of the accessible iommu memory region in the guest is given to the IOMMU by the guest through the mpcifc request specifying the PCI Base Address and the PCI Address Limit. Let set the size of the IOMMU region to: (PCI Address Limit) - (PCI Base Address) + 1. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- hw/s390x/s390-pci-bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c index 69e0671..e97696a 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), - name, iommu->pal + 1); + name, iommu->pal - iommu->pba + 1); iommu->enabled = true; memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); g_free(name); -- 2.7.4 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-10 13:00 ` [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request Pierre Morel @ 2019-01-15 13:59 ` Cornelia Huck 2019-01-15 15:35 ` Collin Walling 2019-01-15 15:47 ` Cornelia Huck 2 siblings, 0 replies; 13+ messages in thread From: Cornelia Huck @ 2019-01-15 13:59 UTC (permalink / raw) To: Pierre Morel, walling Cc: borntraeger, rth, david, qemu-s390x, qemu-devel, pasic, thuth On Thu, 10 Jan 2019 14:00:07 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > The size of the accessible iommu memory region in the guest > is given to the IOMMU by the guest through the mpcifc request > specifying the PCI Base Address and the PCI Address Limit. > > Let set the size of the IOMMU region to: s/Let/Let's/ > (PCI Address Limit) - (PCI Base Address) + 1. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > hw/s390x/s390-pci-bus.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > index 69e0671..e97696a 100644 > --- a/hw/s390x/s390-pci-bus.c > +++ b/hw/s390x/s390-pci-bus.c > @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > - name, iommu->pal + 1); > + name, iommu->pal - iommu->pba + 1); > iommu->enabled = true; > memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > g_free(name); Looks good to me. Collin, can I get an ack from you so I can queue it? ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-10 13:00 ` [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request Pierre Morel 2019-01-15 13:59 ` Cornelia Huck @ 2019-01-15 15:35 ` Collin Walling 2019-01-16 12:40 ` Halil Pasic 2019-01-15 15:47 ` Cornelia Huck 2 siblings, 1 reply; 13+ messages in thread From: Collin Walling @ 2019-01-15 15:35 UTC (permalink / raw) To: Pierre Morel Cc: thuth, david, cohuck, qemu-devel, pasic, borntraeger, qemu-s390x, rth On 1/10/19 8:00 AM, Pierre Morel wrote: > The size of the accessible iommu memory region in the guest > is given to the IOMMU by the guest through the mpcifc request > specifying the PCI Base Address and the PCI Address Limit. > > Let set the size of the IOMMU region to: > (PCI Address Limit) - (PCI Base Address) + 1. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > hw/s390x/s390-pci-bus.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > index 69e0671..e97696a 100644 > --- a/hw/s390x/s390-pci-bus.c > +++ b/hw/s390x/s390-pci-bus.c > @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > - name, iommu->pal + 1); > + name, iommu->pal - iommu->pba + 1); > iommu->enabled = true; > memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > g_free(name); > Acked-by: Collin Walling <walling@linux.ibm.com> ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-15 15:35 ` Collin Walling @ 2019-01-16 12:40 ` Halil Pasic 2019-01-16 14:16 ` Pierre Morel 0 siblings, 1 reply; 13+ messages in thread From: Halil Pasic @ 2019-01-16 12:40 UTC (permalink / raw) To: Collin Walling Cc: Pierre Morel, thuth, david, cohuck, qemu-devel, borntraeger, qemu-s390x, rth On Tue, 15 Jan 2019 10:35:42 -0500 Collin Walling <walling@linux.ibm.com> wrote: > On 1/10/19 8:00 AM, Pierre Morel wrote: > > The size of the accessible iommu memory region in the guest > > is given to the IOMMU by the guest through the mpcifc request > > specifying the PCI Base Address and the PCI Address Limit. > > > > Let set the size of the IOMMU region to: > > (PCI Address Limit) - (PCI Base Address) + 1. > > > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > > --- > > hw/s390x/s390-pci-bus.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > > index 69e0671..e97696a 100644 > > --- a/hw/s390x/s390-pci-bus.c > > +++ b/hw/s390x/s390-pci-bus.c > > @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > > char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > > memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > > TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > > - name, iommu->pal + 1); > > + name, iommu->pal - iommu->pba + 1); From the the look of this, I would say we basically used the address denoting the end of the region as the size of the region. This smells like a bug to me, but the commit message and the title ain't clear about this, and there is no fixes tag. Because of the latter I did some digging and came to commit f7c40aa "s390x/pci: fix failures of dma map/unmap" (Yi Min Zhao, 2016-06-19) which basically did the inverse of this commit! My initial motivation was to check if this is stable material. But now I'm very confused. I'm admittedly zPCI incompetent. Could some of the people that understand what is going on help me feel better about this patch? Regards, Halil > > iommu->enabled = true; > > memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > > g_free(name); > > > > Acked-by: Collin Walling <walling@linux.ibm.com> > > ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 12:40 ` Halil Pasic @ 2019-01-16 14:16 ` Pierre Morel 2019-01-16 14:34 ` Cornelia Huck 2019-01-16 14:50 ` Halil Pasic 0 siblings, 2 replies; 13+ messages in thread From: Pierre Morel @ 2019-01-16 14:16 UTC (permalink / raw) To: Halil Pasic, Collin Walling Cc: thuth, david, cohuck, qemu-devel, borntraeger, qemu-s390x, rth On 16/01/2019 13:40, Halil Pasic wrote: > On Tue, 15 Jan 2019 10:35:42 -0500 > Collin Walling <walling@linux.ibm.com> wrote: > >> On 1/10/19 8:00 AM, Pierre Morel wrote: >>> The size of the accessible iommu memory region in the guest >>> is given to the IOMMU by the guest through the mpcifc request >>> specifying the PCI Base Address and the PCI Address Limit. >>> >>> Let set the size of the IOMMU region to: >>> (PCI Address Limit) - (PCI Base Address) + 1. >>> >>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >>> --- >>> hw/s390x/s390-pci-bus.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c >>> index 69e0671..e97696a 100644 >>> --- a/hw/s390x/s390-pci-bus.c >>> +++ b/hw/s390x/s390-pci-bus.c >>> @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) >>> char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); >>> memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), >>> TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), >>> - name, iommu->pal + 1); >>> + name, iommu->pal - iommu->pba + 1); > > From the the look of this, I would say we basically used the address > denoting the end of the region as the size of the region. This smells > like a bug to me, but the commit message and the title ain't clear about > this, and there is no fixes tag. Because of the latter I did some digging > and came to commit f7c40aa "s390x/pci: fix failures of dma > map/unmap" (Yi Min Zhao, 2016-06-19) which basically did the inverse of > this commit! > > My initial motivation was to check if this is stable material. But now > I'm very confused. I'm admittedly zPCI incompetent. Could some of the > people that understand what is going on help me feel better about this > patch? > > Regards, > Halil The patch you speak about corrected the problem described in its comment by setting the offset address of the subregion to 0, making sure VFIO_PCI works for Z but introduced a bug we did not see at that time by making the subregion too large. This patch correct the bug, I can add a reference to this with: fixing: commit f7c40aa1e7feb50bc4d4bc171fa811bdd9a93e51 Regards, Pierre > > > >>> iommu->enabled = true; >>> memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); >>> g_free(name); >>> >> >> Acked-by: Collin Walling <walling@linux.ibm.com> >> >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 14:16 ` Pierre Morel @ 2019-01-16 14:34 ` Cornelia Huck 2019-01-16 14:50 ` Halil Pasic 1 sibling, 0 replies; 13+ messages in thread From: Cornelia Huck @ 2019-01-16 14:34 UTC (permalink / raw) To: Pierre Morel Cc: Halil Pasic, Collin Walling, thuth, david, qemu-devel, borntraeger, qemu-s390x, rth On Wed, 16 Jan 2019 15:16:44 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 16/01/2019 13:40, Halil Pasic wrote: > > On Tue, 15 Jan 2019 10:35:42 -0500 > > Collin Walling <walling@linux.ibm.com> wrote: > > > >> On 1/10/19 8:00 AM, Pierre Morel wrote: > >>> The size of the accessible iommu memory region in the guest > >>> is given to the IOMMU by the guest through the mpcifc request > >>> specifying the PCI Base Address and the PCI Address Limit. > >>> > >>> Let set the size of the IOMMU region to: > >>> (PCI Address Limit) - (PCI Base Address) + 1. > >>> > >>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > >>> --- > >>> hw/s390x/s390-pci-bus.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > >>> index 69e0671..e97696a 100644 > >>> --- a/hw/s390x/s390-pci-bus.c > >>> +++ b/hw/s390x/s390-pci-bus.c > >>> @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > >>> char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > >>> memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > >>> TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > >>> - name, iommu->pal + 1); > >>> + name, iommu->pal - iommu->pba + 1); > > > > From the the look of this, I would say we basically used the address > > denoting the end of the region as the size of the region. This smells > > like a bug to me, but the commit message and the title ain't clear about > > this, and there is no fixes tag. Because of the latter I did some digging > > and came to commit f7c40aa "s390x/pci: fix failures of dma > > map/unmap" (Yi Min Zhao, 2016-06-19) which basically did the inverse of > > this commit! > > > > My initial motivation was to check if this is stable material. But now > > I'm very confused. I'm admittedly zPCI incompetent. Could some of the > > people that understand what is going on help me feel better about this > > patch? > > > > Regards, > > Halil > > > The patch you speak about corrected the problem described in its comment > by setting the offset address of the subregion to 0, making sure > VFIO_PCI works for Z but introduced a bug we did not see at that time by > making the subregion too large. > > This patch correct the bug, I can add a reference to this with: > fixing: commit f7c40aa1e7feb50bc4d4bc171fa811bdd9a93e51 The patch is already queued, but I can add Fixes: f7c40aa1e7 ("s390x/pci: fix failures of dma map/unmap") > > Regards, > Pierre > > > > > > > > >>> iommu->enabled = true; > >>> memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > >>> g_free(name); > >>> > >> > >> Acked-by: Collin Walling <walling@linux.ibm.com> > >> > >> > > > > ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 14:16 ` Pierre Morel 2019-01-16 14:34 ` Cornelia Huck @ 2019-01-16 14:50 ` Halil Pasic 2019-01-16 15:44 ` Pierre Morel 1 sibling, 1 reply; 13+ messages in thread From: Halil Pasic @ 2019-01-16 14:50 UTC (permalink / raw) To: Pierre Morel Cc: Collin Walling, thuth, david, cohuck, qemu-devel, borntraeger, qemu-s390x, rth On Wed, 16 Jan 2019 15:16:44 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 16/01/2019 13:40, Halil Pasic wrote: > > On Tue, 15 Jan 2019 10:35:42 -0500 > > Collin Walling <walling@linux.ibm.com> wrote: > > > >> On 1/10/19 8:00 AM, Pierre Morel wrote: > >>> The size of the accessible iommu memory region in the guest > >>> is given to the IOMMU by the guest through the mpcifc request > >>> specifying the PCI Base Address and the PCI Address Limit. > >>> > >>> Let set the size of the IOMMU region to: > >>> (PCI Address Limit) - (PCI Base Address) + 1. > >>> > >>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > >>> --- > >>> hw/s390x/s390-pci-bus.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > >>> index 69e0671..e97696a 100644 > >>> --- a/hw/s390x/s390-pci-bus.c > >>> +++ b/hw/s390x/s390-pci-bus.c > >>> @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > >>> char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > >>> memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > >>> TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > >>> - name, iommu->pal + 1); > >>> + name, iommu->pal - iommu->pba + 1); > > > > From the the look of this, I would say we basically used the address > > denoting the end of the region as the size of the region. This smells > > like a bug to me, but the commit message and the title ain't clear about > > this, and there is no fixes tag. Because of the latter I did some digging > > and came to commit f7c40aa "s390x/pci: fix failures of dma > > map/unmap" (Yi Min Zhao, 2016-06-19) which basically did the inverse of > > this commit! > > > > My initial motivation was to check if this is stable material. But now > > I'm very confused. I'm admittedly zPCI incompetent. Could some of the > > people that understand what is going on help me feel better about this > > patch? > > > > Regards, > > Halil > > > The patch you speak about corrected the problem described in its comment > by setting the offset address of the subregion to 0, making sure > VFIO_PCI works for Z but introduced a bug we did not see at that time by > making the subregion too large. > > This patch correct the bug, I can add a reference to this with: > fixing: commit f7c40aa1e7feb50bc4d4bc171fa811bdd9a93e51 > @Connie, will you add the Fixes tag? Do we need a cc stable (since broken since 2016-06-19)? @Pierre: So you say it's a bug. What can go wrong because of this? For example if we interpret pal as a size, I guess we could end up with the memory region not fitting the guest memory, or? I'm still pretty much in the dark about the implications of this bug. Regards, Halil ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 14:50 ` Halil Pasic @ 2019-01-16 15:44 ` Pierre Morel 2019-01-16 16:41 ` Cornelia Huck 0 siblings, 1 reply; 13+ messages in thread From: Pierre Morel @ 2019-01-16 15:44 UTC (permalink / raw) To: Halil Pasic Cc: Collin Walling, thuth, david, cohuck, qemu-devel, borntraeger, qemu-s390x, rth On 16/01/2019 15:50, Halil Pasic wrote: > On Wed, 16 Jan 2019 15:16:44 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> On 16/01/2019 13:40, Halil Pasic wrote: >>> On Tue, 15 Jan 2019 10:35:42 -0500 >>> Collin Walling <walling@linux.ibm.com> wrote: >>> >>>> On 1/10/19 8:00 AM, Pierre Morel wrote: >>>>> The size of the accessible iommu memory region in the guest >>>>> is given to the IOMMU by the guest through the mpcifc request >>>>> specifying the PCI Base Address and the PCI Address Limit. >>>>> >>>>> Let set the size of the IOMMU region to: >>>>> (PCI Address Limit) - (PCI Base Address) + 1. >>>>> >>>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >>>>> --- >>>>> hw/s390x/s390-pci-bus.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c >>>>> index 69e0671..e97696a 100644 >>>>> --- a/hw/s390x/s390-pci-bus.c >>>>> +++ b/hw/s390x/s390-pci-bus.c >>>>> @@ -660,7 +660,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) >>>>> char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); >>>>> memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), >>>>> TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), >>>>> - name, iommu->pal + 1); >>>>> + name, iommu->pal - iommu->pba + 1); >>> >>> From the the look of this, I would say we basically used the address >>> denoting the end of the region as the size of the region. This smells >>> like a bug to me, but the commit message and the title ain't clear about >>> this, and there is no fixes tag. Because of the latter I did some digging >>> and came to commit f7c40aa "s390x/pci: fix failures of dma >>> map/unmap" (Yi Min Zhao, 2016-06-19) which basically did the inverse of >>> this commit! >>> >>> My initial motivation was to check if this is stable material. But now >>> I'm very confused. I'm admittedly zPCI incompetent. Could some of the >>> people that understand what is going on help me feel better about this >>> patch? >>> >>> Regards, >>> Halil >> >> >> The patch you speak about corrected the problem described in its comment >> by setting the offset address of the subregion to 0, making sure >> VFIO_PCI works for Z but introduced a bug we did not see at that time by >> making the subregion too large. >> >> This patch correct the bug, I can add a reference to this with: >> fixing: commit f7c40aa1e7feb50bc4d4bc171fa811bdd9a93e51 >> > > @Connie, will you add the Fixes tag? Do we need a cc stable (since > broken since 2016-06-19)? > > @Pierre: So you say it's a bug. > What can go wrong because of this? > For example if we interpret pal as a size, I guess we could end up with > the memory region not fitting the guest memory, The memory region will be too large compared with what the guest required. > or? I'm still pretty > much in the dark about the implications of this bug. > > Regards, > Halil > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 15:44 ` Pierre Morel @ 2019-01-16 16:41 ` Cornelia Huck 2019-01-17 15:13 ` Halil Pasic 0 siblings, 1 reply; 13+ messages in thread From: Cornelia Huck @ 2019-01-16 16:41 UTC (permalink / raw) To: Pierre Morel Cc: Halil Pasic, Collin Walling, thuth, david, qemu-devel, borntraeger, qemu-s390x, rth On Wed, 16 Jan 2019 16:44:09 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > On 16/01/2019 15:50, Halil Pasic wrote: > > @Connie, will you add the Fixes tag? Do we need a cc stable (since > > broken since 2016-06-19)? > > > > @Pierre: So you say it's a bug. > > What can go wrong because of this? > > For example if we interpret pal as a size, I guess we could end up with > > the memory region not fitting the guest memory, > > The memory region will be too large compared with what the guest required. Honestly, this does not look like QEMU stable material to me. ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-16 16:41 ` Cornelia Huck @ 2019-01-17 15:13 ` Halil Pasic 0 siblings, 0 replies; 13+ messages in thread From: Halil Pasic @ 2019-01-17 15:13 UTC (permalink / raw) To: Cornelia Huck Cc: Pierre Morel, Collin Walling, david, qemu-devel, borntraeger, qemu-s390x, thuth, rth On Wed, 16 Jan 2019 17:41:30 +0100 Cornelia Huck <cohuck@redhat.com> wrote: > On Wed, 16 Jan 2019 16:44:09 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > > > On 16/01/2019 15:50, Halil Pasic wrote: > > > > @Connie, will you add the Fixes tag? Do we need a cc stable (since > > > broken since 2016-06-19)? > > > > > > @Pierre: So you say it's a bug. > > > What can go wrong because of this? > > > For example if we interpret pal as a size, I guess we could end up with > > > the memory region not fitting the guest memory, > > > > The memory region will be too large compared with what the guest required. > > Honestly, this does not look like QEMU stable material to me. > Based on Pierre's offline explanation, from which I understood, the worst thing that can happen is, that a buggy guest can render it's pci function unusable, I have to agree: not stable material. My problem is my non-existent understanding of zPCI. My intuition was this should be much nastier than that. I would have appreciated a better explanation on why this is not a problem in practice though -- best as a part of the commit message. Regards, Halil ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-10 13:00 ` [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request Pierre Morel 2019-01-15 13:59 ` Cornelia Huck 2019-01-15 15:35 ` Collin Walling @ 2019-01-15 15:47 ` Cornelia Huck 2019-01-15 17:35 ` Pierre Morel 2 siblings, 1 reply; 13+ messages in thread From: Cornelia Huck @ 2019-01-15 15:47 UTC (permalink / raw) To: Pierre Morel Cc: walling, borntraeger, rth, david, qemu-s390x, qemu-devel, pasic, thuth On Thu, 10 Jan 2019 14:00:07 +0100 Pierre Morel <pmorel@linux.ibm.com> wrote: > The size of the accessible iommu memory region in the guest > is given to the IOMMU by the guest through the mpcifc request > specifying the PCI Base Address and the PCI Address Limit. > > Let set the size of the IOMMU region to: > (PCI Address Limit) - (PCI Base Address) + 1. > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > hw/s390x/s390-pci-bus.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Thanks, applied. ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request 2019-01-15 15:47 ` Cornelia Huck @ 2019-01-15 17:35 ` Pierre Morel 0 siblings, 0 replies; 13+ messages in thread From: Pierre Morel @ 2019-01-15 17:35 UTC (permalink / raw) To: Cornelia Huck Cc: walling, borntraeger, rth, david, qemu-s390x, qemu-devel, pasic, thuth On 15/01/2019 16:47, Cornelia Huck wrote: > On Thu, 10 Jan 2019 14:00:07 +0100 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> The size of the accessible iommu memory region in the guest >> is given to the IOMMU by the guest through the mpcifc request >> specifying the PCI Base Address and the PCI Address Limit. >> >> Let set the size of the IOMMU region to: >> (PCI Address Limit) - (PCI Base Address) + 1. >> >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >> --- >> hw/s390x/s390-pci-bus.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > Thanks, applied. > Thanks. :) -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany ^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2019-01-17 15:14 UTC | newest] Thread overview: 13+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-01-10 13:00 [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size as guest wants Pierre Morel 2019-01-10 13:00 ` [Qemu-devel] [PATCH v2] s390x/pci: Set the iommu region size mpcifc request Pierre Morel 2019-01-15 13:59 ` Cornelia Huck 2019-01-15 15:35 ` Collin Walling 2019-01-16 12:40 ` Halil Pasic 2019-01-16 14:16 ` Pierre Morel 2019-01-16 14:34 ` Cornelia Huck 2019-01-16 14:50 ` Halil Pasic 2019-01-16 15:44 ` Pierre Morel 2019-01-16 16:41 ` Cornelia Huck 2019-01-17 15:13 ` Halil Pasic 2019-01-15 15:47 ` Cornelia Huck 2019-01-15 17:35 ` Pierre Morel
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