> -----Original Message-----
> From: Jan Beulich [mailto:jbeul...@suse.com]
> Sent: 06 September 2018 14:04
> To: xen-devel <xen-devel@lists.xenproject.org>
> Cc: Olaf Hering <o...@aepfle.de>; Andrew Cooper
> <andrew.coop...@citrix.com>; Paul Durrant <paul.durr...@citrix.com>
> Subject: [PATCH v3 2/3] x86/HVM: add known_gla() emulation helper
>
> ... as a central place to do respective checking for whether the
> translation for the linear address is available as well as usable.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
> ---
> v3: Split from subsequent patch.
Much nicer :-)
Reviewed-by: Paul Durrant <paul.durr...@citrix.com>
>
> --- a/xen/arch/x86/hvm/emulate.c
> +++ b/xen/arch/x86/hvm/emulate.c
> @@ -1041,6 +1041,26 @@ static inline int hvmemul_linear_mmio_wr
> pfec, hvmemul_ctxt, translate);
> }
>
> +static bool known_gla(unsigned long addr, unsigned int bytes, uint32_t
> pfec)
> +{
> + const struct hvm_vcpu_io *vio = ¤t->arch.hvm.hvm_io;
> +
> + if ( pfec & PFEC_write_access )
> + {
> + if ( !vio->mmio_access.write_access )
> + return false;
> + }
> + else if ( pfec & PFEC_insn_fetch )
> + {
> + if ( !vio->mmio_access.insn_fetch )
> + return false;
> + }
> + else if ( !vio->mmio_access.read_access )
> + return false;
> +
> + return vio->mmio_gla == (addr & PAGE_MASK);
> +}
> +
> static int __hvmemul_read(
> enum x86_segment seg,
> unsigned long offset,
> @@ -1049,11 +1069,9 @@ static int __hvmemul_read(
> enum hvm_access_type access_type,
> struct hvm_emulate_ctxt *hvmemul_ctxt)
> {
> - struct vcpu *curr = current;
> pagefault_info_t pfinfo;
> unsigned long addr, reps = 1;
> uint32_t pfec = PFEC_page_present;
> - struct hvm_vcpu_io *vio = &curr->arch.hvm.hvm_io;
> int rc;
>
> if ( is_x86_system_segment(seg) )
> @@ -1067,10 +1085,7 @@ static int __hvmemul_read(
> seg, offset, bytes, &reps, access_type, hvmemul_ctxt, &addr);
> if ( rc != X86EMUL_OKAY || !bytes )
> return rc;
> - if ( ((access_type != hvm_access_insn_fetch
> - ? vio->mmio_access.read_access
> - : vio->mmio_access.insn_fetch)) &&
> - (vio->mmio_gla == (addr & PAGE_MASK)) )
> + if ( known_gla(addr, bytes, pfec) )
> return hvmemul_linear_mmio_read(addr, bytes, p_data, pfec,
> hvmemul_ctxt, 1);
>
> rc = hvm_copy_from_guest_linear(p_data, addr, bytes, pfec, &pfinfo);
> @@ -1171,10 +1186,8 @@ static int hvmemul_write(
> {
> struct hvm_emulate_ctxt *hvmemul_ctxt =
> container_of(ctxt, struct hvm_emulate_ctxt, ctxt);
> - struct vcpu *curr = current;
> unsigned long addr, reps = 1;
> uint32_t pfec = PFEC_page_present | PFEC_write_access;
> - struct hvm_vcpu_io *vio = &curr->arch.hvm.hvm_io;
> int rc;
> void *mapping;
>
> @@ -1188,8 +1201,7 @@ static int hvmemul_write(
> if ( rc != X86EMUL_OKAY || !bytes )
> return rc;
>
> - if ( vio->mmio_access.write_access &&
> - (vio->mmio_gla == (addr & PAGE_MASK)) )
> + if ( known_gla(addr, bytes, pfec) )
> return hvmemul_linear_mmio_write(addr, bytes, p_data, pfec,
> hvmemul_ctxt, 1);
>
> mapping = hvmemul_map_linear_addr(addr, bytes, pfec, hvmemul_ctxt);
> @@ -1218,7 +1230,6 @@ static int hvmemul_rmw(
> container_of(ctxt, struct hvm_emulate_ctxt, ctxt);
> unsigned long addr, reps = 1;
> uint32_t pfec = PFEC_page_present | PFEC_write_access;
> - struct hvm_vcpu_io *vio = ¤t->arch.hvm.hvm_io;
> int rc;
> void *mapping;
>
> @@ -1244,8 +1255,7 @@ static int hvmemul_rmw(
> else
> {
> unsigned long data = 0;
> - bool known_gpfn = vio->mmio_access.write_access &&
> - vio->mmio_gla == (addr & PAGE_MASK);
> + bool known_gpfn = known_gla(addr, bytes, pfec);
>
> if ( bytes > sizeof(data) )
> return X86EMUL_UNHANDLEABLE;
>
>
>
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