From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Ram Pai <linuxram@us.ibm.com>, linuxppc-dev@lists.ozlabs.org
Cc: andmike@us.ibm.com, mst@redhat.com, mdroth@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, ram.n.pai@gmail.com, cai@lca.pw,
tglx@linutronix.de, sukadev@linux.vnet.ibm.com, hch@lst.de,
bauerman@linux.ibm.com, david@gibson.dropbear.id.au
Subject: Re: [RFC v1 1/2] powerpc/pseries/iommu: Share the per-cpu TCE page with the hypervisor.
Date: Wed, 6 Nov 2019 12:58:50 +1100 [thread overview]
Message-ID: <af0a236f-37b2-ee16-0ebd-576b4e12d8cd@ozlabs.ru> (raw)
In-Reply-To: <1572902923-8096-2-git-send-email-linuxram@us.ibm.com>
On 05/11/2019 08:28, Ram Pai wrote:
> The hypervisor needs to access the contents of the page holding the TCE
> entries while setting up the TCE entries in the IOMMU's TCE table. For
> SecureVMs, since this page is encrypted, the hypervisor cannot access
> valid entries. Share the page with the hypervisor. This ensures that the
> hypervisor sees the valid entries.
>
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
> arch/powerpc/platforms/pseries/iommu.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 8d9c2b1..07f0847 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -37,6 +37,7 @@
> #include <asm/mmzone.h>
> #include <asm/plpar_wrappers.h>
> #include <asm/svm.h>
> +#include <asm/ultravisor.h>
>
> #include "pseries.h"
>
> @@ -179,6 +180,19 @@ static int tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
>
> static DEFINE_PER_CPU(__be64 *, tce_page);
>
> +/*
> + * Allocate a tce page. If secure VM, share the page with the hypervisor.
> + */
> +static __be64 *alloc_tce_page(void)
> +{
> + __be64 *tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
> +
> + if (tcep && is_secure_guest())
> + uv_share_page(PHYS_PFN(__pa(tcep)), 1);
There is no matching unshare in this patch.
> +
> + return tcep;
> +}
> +
> static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
> long npages, unsigned long uaddr,
> enum dma_data_direction direction,
> @@ -206,8 +220,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
> * from iommu_alloc{,_sg}()
> */
> if (!tcep) {
> - tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
> - /* If allocation fails, fall back to the loop implementation */
> + tcep = alloc_tce_page();
> if (!tcep) {
> local_irq_restore(flags);
> return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
> @@ -391,6 +404,7 @@ static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
> return rc;
> }
>
> +
Unrelated.
> static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
> unsigned long num_pfn, const void *arg)
> {
> @@ -405,7 +419,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
> tcep = __this_cpu_read(tce_page);
>
> if (!tcep) {
> - tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
> + tcep = alloc_tce_page();
> if (!tcep) {
> local_irq_enable();
> return -ENOMEM;
>
--
Alexey
next prev parent reply other threads:[~2019-11-06 2:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 21:28 [RFC v1 0/2] Enable IOMMU support for pseries Secure VMs Ram Pai
2019-11-04 21:28 ` [RFC v1 1/2] powerpc/pseries/iommu: Share the per-cpu TCE page with the hypervisor Ram Pai
2019-11-04 21:28 ` [RFC v1 2/2] powerpc/pseries/iommu: Use dma_iommu_ops for Secure VMs aswell Ram Pai
2019-11-07 10:26 ` Michael Ellerman
2019-11-08 5:49 ` Ram Pai
2019-11-06 1:58 ` Alexey Kardashevskiy [this message]
2019-11-06 17:01 ` [RFC v1 1/2] powerpc/pseries/iommu: Share the per-cpu TCE page with the hypervisor Ram Pai
2019-11-07 5:58 ` Alexey Kardashevskiy
2019-11-07 10:29 ` Michael Ellerman
2019-11-08 6:05 ` Ram Pai
2019-11-06 1:59 ` [RFC v1 0/2] Enable IOMMU support for pseries Secure VMs Alexey Kardashevskiy
2019-11-06 16:46 ` Ram Pai
2019-11-06 18:06 ` Michael S. Tsirkin
2019-11-06 18:52 ` Michael Roth
2019-11-06 22:22 ` Ram Pai
2019-11-07 6:01 ` Alexey Kardashevskiy
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