Ping, any thoughts on this are appreciated.
Regards,
Alex
On 11.01.2019 17:37, Alexandru Stefan ISAILA wrote:
> This is done so hvmemul_linear_to_phys() can be called from
> hvmemul_map_linear_addr()
>
> Signed-off-by: Alexandru Isaila <aisa...@bitdefender.com>
> ---
> xen/arch/x86/hvm/emulate.c | 181 ++++++++++++++++++-------------------
> 1 file changed, 90 insertions(+), 91 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
> index 2d02ef1521..a766eecc8e 100644
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -530,6 +530,95 @@ static int hvmemul_do_mmio_addr(paddr_t mmio_gpa,
> return hvmemul_do_io_addr(1, mmio_gpa, reps, size, dir, df, ram_gpa);
> }
>
> +/*
> + * Convert addr from linear to physical form, valid over the range
> + * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
> + * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
> + * @pfec indicates the access checks to be performed during page-table walks.
> + */
> +static int hvmemul_linear_to_phys(
> + unsigned long addr,
> + paddr_t *paddr,
> + unsigned int bytes_per_rep,
> + unsigned long *reps,
> + uint32_t pfec,
> + struct hvm_emulate_ctxt *hvmemul_ctxt)
> +{
> + struct vcpu *curr = current;
> + unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
> + int reverse;
> +
> + /*
> + * Clip repetitions to a sensible maximum. This avoids extensive looping
> in
> + * this function while still amortising the cost of I/O trap-and-emulate.
> + */
> + *reps = min_t(unsigned long, *reps, 4096);
> +
> + /* With no paging it's easy: linear == physical. */
> + if ( !(curr->arch.hvm.guest_cr[0] & X86_CR0_PG) )
> + {
> + *paddr = addr;
> + return X86EMUL_OKAY;
> + }
> +
> + /* Reverse mode if this is a backwards multi-iteration string operation.
> */
> + reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps >
> 1);
> +
> + if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
> + {
> + /* Do page-straddling first iteration forwards via recursion. */
> + paddr_t _paddr;
> + unsigned long one_rep = 1;
> + int rc = hvmemul_linear_to_phys(
> + addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
> + if ( rc != X86EMUL_OKAY )
> + return rc;
> + pfn = _paddr >> PAGE_SHIFT;
> + }
> + else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) ==
> gfn_x(INVALID_GFN) )
> + {
> + if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> + return X86EMUL_RETRY;
> + *reps = 0;
> + x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
> + return X86EMUL_EXCEPTION;
> + }
> +
> + done = reverse ? bytes_per_rep + offset : PAGE_SIZE - offset;
> + todo = *reps * bytes_per_rep;
> + for ( i = 1; done < todo; i++ )
> + {
> + /* Get the next PFN in the range. */
> + addr += reverse ? -PAGE_SIZE : PAGE_SIZE;
> + npfn = paging_gva_to_gfn(curr, addr, &pfec);
> +
> + /* Is it contiguous with the preceding PFNs? If not then we're done.
> */
> + if ( (npfn == gfn_x(INVALID_GFN)) ||
> + (npfn != (pfn + (reverse ? -i : i))) )
> + {
> + if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> + return X86EMUL_RETRY;
> + done /= bytes_per_rep;
> + if ( done == 0 )
> + {
> + ASSERT(!reverse);
> + if ( npfn != gfn_x(INVALID_GFN) )
> + return X86EMUL_UNHANDLEABLE;
> + *reps = 0;
> + x86_emul_pagefault(pfec, addr & PAGE_MASK,
> &hvmemul_ctxt->ctxt);
> + return X86EMUL_EXCEPTION;
> + }
> + *reps = done;
> + break;
> + }
> +
> + done += PAGE_SIZE;
> + }
> +
> + *paddr = ((paddr_t)pfn << PAGE_SHIFT) | offset;
> + return X86EMUL_OKAY;
> +}
> +
> /*
> * Map the frame(s) covering an individual linear access, for writeable
> * access. May return NULL for MMIO, or ERR_PTR(~X86EMUL_*) for other
> errors
> @@ -692,97 +781,7 @@ static void hvmemul_unmap_linear_addr(
> *mfn++ = _mfn(0);
> }
> #endif
> -}
> -
> -/*
> - * Convert addr from linear to physical form, valid over the range
> - * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
> - * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
> - * @pfec indicates the access checks to be performed during page-table walks.
> - */
> -static int hvmemul_linear_to_phys(
> - unsigned long addr,
> - paddr_t *paddr,
> - unsigned int bytes_per_rep,
> - unsigned long *reps,
> - uint32_t pfec,
> - struct hvm_emulate_ctxt *hvmemul_ctxt)
> -{
> - struct vcpu *curr = current;
> - unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
> - int reverse;
> -
> - /*
> - * Clip repetitions to a sensible maximum. This avoids extensive looping
> in
> - * this function while still amortising the cost of I/O trap-and-emulate.
> - */
> - *reps = min_t(unsigned long, *reps, 4096);
> -
> - /* With no paging it's easy: linear == physical. */
> - if ( !(curr->arch.hvm.guest_cr[0] & X86_CR0_PG) )
> - {
> - *paddr = addr;
> - return X86EMUL_OKAY;
> - }
> -
> - /* Reverse mode if this is a backwards multi-iteration string operation.
> */
> - reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps >
> 1);
> -
> - if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
> - {
> - /* Do page-straddling first iteration forwards via recursion. */
> - paddr_t _paddr;
> - unsigned long one_rep = 1;
> - int rc = hvmemul_linear_to_phys(
> - addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
> - if ( rc != X86EMUL_OKAY )
> - return rc;
> - pfn = _paddr >> PAGE_SHIFT;
> - }
> - else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) ==
> gfn_x(INVALID_GFN) )
> - {
> - if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> - return X86EMUL_RETRY;
> - *reps = 0;
> - x86_emul_pagefault(pfec, addr, &hvmemul_ctxt->ctxt);
> - return X86EMUL_EXCEPTION;
> - }
> -
> - done = reverse ? bytes_per_rep + offset : PAGE_SIZE - offset;
> - todo = *reps * bytes_per_rep;
> - for ( i = 1; done < todo; i++ )
> - {
> - /* Get the next PFN in the range. */
> - addr += reverse ? -PAGE_SIZE : PAGE_SIZE;
> - npfn = paging_gva_to_gfn(curr, addr, &pfec);
> -
> - /* Is it contiguous with the preceding PFNs? If not then we're done.
> */
> - if ( (npfn == gfn_x(INVALID_GFN)) ||
> - (npfn != (pfn + (reverse ? -i : i))) )
> - {
> - if ( pfec & (PFEC_page_paged | PFEC_page_shared) )
> - return X86EMUL_RETRY;
> - done /= bytes_per_rep;
> - if ( done == 0 )
> - {
> - ASSERT(!reverse);
> - if ( npfn != gfn_x(INVALID_GFN) )
> - return X86EMUL_UNHANDLEABLE;
> - *reps = 0;
> - x86_emul_pagefault(pfec, addr & PAGE_MASK,
> &hvmemul_ctxt->ctxt);
> - return X86EMUL_EXCEPTION;
> - }
> - *reps = done;
> - break;
> - }
> -
> - done += PAGE_SIZE;
> - }
> -
> - *paddr = ((paddr_t)pfn << PAGE_SHIFT) | offset;
> - return X86EMUL_OKAY;
> -}
> -
> +}
>
> static int hvmemul_virtual_to_linear(
> enum x86_segment seg,
>
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