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Date: Mon, 22 Oct 2012 14:46:04 +0100
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
"mukesh.rathor@...cle.com" <mukesh.rathor@...cle.com>,
Ian Campbell <Ian.Campbell@...rix.com>,
Stefano Stabellini <Stefano.Stabellini@...citrix.com>
Subject: Re: [PATCH 3/6] xen/pvh: Implements mmu changes for PVH.
On Sat, 20 Oct 2012, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@...cle.com>
>
> First the set/clear mmio pte function makes a hypercall to update the
> P2M in Xen with 1:1 mapping. Since PVH uses mostly native mmu ops, we
> leave the generic (native_*) for the rest.
>
> Two local functions are introduced to add to xen physmap for xen remap
> interface. Xen unmap interface is introduced so the privcmd pte entries
> can be cleared in Xen p2m table.
>
> Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
this patch looks all right, but I would like to read Ian's feedback too
> arch/x86/xen/mmu.c | 162 +++++++++++++++++++++++++++++++++++++++++++++++--
> arch/x86/xen/mmu.h | 2 +
> drivers/xen/privcmd.c | 5 +-
> include/xen/xen-ops.h | 5 +-
> 4 files changed, 165 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 6226c99..5747a41 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -74,6 +74,7 @@
> #include <xen/interface/version.h>
> #include <xen/interface/memory.h>
> #include <xen/hvc-console.h>
> +#include <xen/balloon.h>
>
> #include "multicalls.h"
> #include "mmu.h"
> @@ -332,6 +333,20 @@ static void xen_set_pte(pte_t *ptep, pte_t pteval)
> __xen_set_pte(ptep, pteval);
> }
>
> +void xen_set_clr_mmio_pvh_pte(unsigned long pfn, unsigned long mfn,
> + int nr_mfns, int add_mapping)
> +{
> + struct physdev_map_iomem iomem;
> +
> + iomem.first_gfn = pfn;
> + iomem.first_mfn = mfn;
> + iomem.nr_mfns = nr_mfns;
> + iomem.add_mapping = add_mapping;
> +
> + if (HYPERVISOR_physdev_op(PHYSDEVOP_map_iomem, &iomem))
> + BUG();
> +}
> +
> static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
> pte_t *ptep, pte_t pteval)
> {
> @@ -1221,6 +1236,8 @@ static void __init xen_pagetable_init(void)
> #endif
> paging_init();
> xen_setup_shared_info();
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return;
> #ifdef CONFIG_X86_64
> if (!xen_feature(XENFEAT_auto_translated_physmap)) {
> unsigned long new_mfn_list;
> @@ -1528,6 +1545,10 @@ static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
> static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
> {
> struct mmuext_op op;
> +
> + if (xen_feature(XENFEAT_writable_page_tables))
> + return;
> +
> op.cmd = cmd;
> op.arg1.mfn = pfn_to_mfn(pfn);
> if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
> @@ -1725,6 +1746,10 @@ static void set_page_prot(void *addr, pgprot_t prot)
> unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
> pte_t pte = pfn_pte(pfn, prot);
>
> + /* recall for PVH, page tables are native. */
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return;
> +
> if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
> BUG();
> }
> @@ -1802,6 +1827,9 @@ static void convert_pfn_mfn(void *v)
> pte_t *pte = v;
> int i;
>
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return;
> +
> /* All levels are converted the same way, so just treat them
> as ptes. */
> for (i = 0; i < PTRS_PER_PTE; i++)
> @@ -1821,6 +1849,7 @@ static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
> (*pt_end)--;
> }
> }
> +
> /*
> * Set up the initial kernel pagetable.
> *
> @@ -1831,6 +1860,7 @@ static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
> * but that's enough to get __va working. We need to fill in the rest
> * of the physical mapping once some sort of allocator has been set
> * up.
> + * NOTE: for PVH, the page tables are native.
> */
> void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
> {
> @@ -1908,10 +1938,13 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
> * structure to attach it to, so make sure we just set kernel
> * pgd.
> */
> - xen_mc_batch();
> - __xen_write_cr3(true, __pa(init_level4_pgt));
> - xen_mc_issue(PARAVIRT_LAZY_CPU);
> -
> + if (xen_feature(XENFEAT_writable_page_tables)) {
> + native_write_cr3(__pa(init_level4_pgt));
> + } else {
> + xen_mc_batch();
> + __xen_write_cr3(true, __pa(init_level4_pgt));
> + xen_mc_issue(PARAVIRT_LAZY_CPU);
> + }
> /* We can't that easily rip out L3 and L2, as the Xen pagetables are
> * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
> * the initial domain. For guests using the toolstack, they are in:
> @@ -2178,8 +2211,13 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
>
> void __init xen_init_mmu_ops(void)
> {
> - x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
> x86_init.paging.pagetable_init = xen_pagetable_init;
> +
> + if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + pv_mmu_ops.flush_tlb_others = xen_flush_tlb_others;
> + return;
> + }
> + x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
> pv_mmu_ops = xen_mmu_ops;
>
> memset(dummy_mapping, 0xff, PAGE_SIZE);
> @@ -2455,6 +2493,89 @@ void __init xen_hvm_init_mmu_ops(void)
> }
> #endif
>
> +/* Map foreign gmfn, fgmfn, to local pfn, lpfn. This for the user space
> + * creating new guest on PVH dom0 and needs to map domU pages.
> + */
> +static int pvh_add_to_xen_p2m(unsigned long lpfn, unsigned long fgmfn,
> + unsigned int domid)
> +{
> + int rc;
> + struct xen_add_to_physmap xatp = { .foreign_domid = domid };
> +
> + xatp.gpfn = lpfn;
> + xatp.idx = fgmfn;
> + xatp.domid = DOMID_SELF;
> + xatp.space = XENMAPSPACE_gmfn_foreign;
> + rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
> + if (rc)
> + pr_warn("d0: Failed to map pfn (0x%lx) to mfn (0x%lx) rc:%d\n",
> + lpfn, fgmfn, rc);
> + return rc;
> +}
> +
> +static int pvh_rem_xen_p2m(unsigned long spfn, int count)
> +{
> + struct xen_remove_from_physmap xrp;
> + int i, rc;
> +
> + for (i = 0; i < count; i++) {
> + xrp.domid = DOMID_SELF;
> + xrp.gpfn = spfn+i;
> + rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
> + if (rc) {
> + pr_warn("Failed to unmap pfn:%lx rc:%d done:%d\n",
> + spfn+i, rc, i);
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> +struct pvh_remap_data {
> + unsigned long fgmfn; /* foreign domain's gmfn */
> + pgprot_t prot;
> + domid_t domid;
> + int index;
> + struct page **pages;
> +};
> +
> +static int pvh_map_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
> + void *data)
> +{
> + int rc;
> + struct pvh_remap_data *remap = data;
> + unsigned long pfn = page_to_pfn(remap->pages[remap->index++]);
> + pte_t pteval = pte_mkspecial(pfn_pte(pfn, remap->prot));
> +
> + rc = pvh_add_to_xen_p2m(pfn, remap->fgmfn, remap->domid);
> + if (rc)
> + return rc;
> + native_set_pte(ptep, pteval);
> +
> + return 0;
> +}
> +
> +static int pvh_remap_gmfn_range(struct vm_area_struct *vma,
> + unsigned long addr, unsigned long mfn, int nr,
> + pgprot_t prot, unsigned domid,
> + struct page **pages)
> +{
> + int err;
> + struct pvh_remap_data pvhdata;
> +
> + BUG_ON(!pages);
> +
> + pvhdata.fgmfn = mfn;
> + pvhdata.prot = prot;
> + pvhdata.domid = domid;
> + pvhdata.index = 0;
> + pvhdata.pages = pages;
> + err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
> + pvh_map_pte_fn, &pvhdata);
> + flush_tlb_all();
> + return err;
> +}
> +
> #define REMAP_BATCH_SIZE 16
>
> struct remap_data {
> @@ -2479,7 +2600,9 @@ static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
> int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
> unsigned long addr,
> unsigned long mfn, int nr,
> - pgprot_t prot, unsigned domid)
> + pgprot_t prot, unsigned domid,
> + struct page **pages)
> +
> {
> struct remap_data rmd;
> struct mmu_update mmu_update[REMAP_BATCH_SIZE];
> @@ -2494,6 +2617,10 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
>
> BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
>
> + if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + /* We need to update the local page tables and the xen HAP */
> + return pvh_remap_gmfn_range(vma, addr, mfn, nr, prot, domid, pages);
> + }
> rmd.mfn = mfn;
> rmd.prot = prot;
>
> @@ -2523,3 +2650,26 @@ out:
> return err;
> }
> EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
> +
> +/* Returns: 0 success */
> +int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
> + int numpgs, struct page **pages)
> +{
> + if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
> + return 0;
> +
> + while (numpgs--) {
> +
> + /* the mmu has already cleaned up the process mmu resources at
> + * this point (lookup_address will return NULL). */
> + unsigned long pfn = page_to_pfn(pages[numpgs]);
> +
> + pvh_rem_xen_p2m(pfn, 1);
> + }
> + /* We don't need to flush tlbs because as part of pvh_rem_xen_p2m(),
> + * the hypervisor will do tlb flushes after removing the p2m entries
> + * from the EPT/NPT */
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
> diff --git a/arch/x86/xen/mmu.h b/arch/x86/xen/mmu.h
> index 73809bb..6d0bb56 100644
> --- a/arch/x86/xen/mmu.h
> +++ b/arch/x86/xen/mmu.h
> @@ -23,4 +23,6 @@ unsigned long xen_read_cr2_direct(void);
>
> extern void xen_init_mmu_ops(void);
> extern void xen_hvm_init_mmu_ops(void);
> +extern void xen_set_clr_mmio_pvh_pte(unsigned long pfn, unsigned long mfn,
> + int nr_mfns, int add_mapping);
> #endif /* _XEN_MMU_H */
> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
> index 8adb9cc..b612267 100644
> --- a/drivers/xen/privcmd.c
> +++ b/drivers/xen/privcmd.c
> @@ -178,7 +178,7 @@ static int mmap_mfn_range(void *data, void *state)
> msg->va & PAGE_MASK,
> msg->mfn, msg->npages,
> vma->vm_page_prot,
> - st->domain);
> + st->domain, NULL);
> if (rc < 0)
> return rc;
>
> @@ -267,7 +267,8 @@ static int mmap_batch_fn(void *data, void *state)
> int ret;
>
> ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
> - st->vma->vm_page_prot, st->domain);
> + st->vma->vm_page_prot, st->domain,
> + NULL);
>
> /* Store error code for second pass. */
> *(st->err++) = ret;
> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> index 6a198e4..990b43e 100644
> --- a/include/xen/xen-ops.h
> +++ b/include/xen/xen-ops.h
> @@ -27,6 +27,9 @@ struct vm_area_struct;
> int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
> unsigned long addr,
> unsigned long mfn, int nr,
> - pgprot_t prot, unsigned domid);
> + pgprot_t prot, unsigned domid,
> + struct page **pages);
> +int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
> + int numpgs, struct page **pages);
>
> #endif /* INCLUDE_XEN_OPS_H */
> --
> 1.7.7.6
>
--
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