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s=corp-2020-01-29; bh=e5kvjTNHNZ5bZzwKzEgSd2kZPMSBlSOmboG8wtJ3sfg=; b=cN4Dx+o3/OP0VaT3D9MWwzuLuQMBERnsYuO0VksUB1jyDZ8v8z5N8Vts54r8gzw7ph0k h8/u39QXHtgTIhFbJXLH50WvxmniWdq7qhBzRobOCXbFgk0RSHsB7+0JbAYM6eK63EEc zbIy22RYAgXfeycoZ3wR8HR+U0fsuoq1yOOhHX9omSd+Ncpbz5eWXdh2ocLZi4QOmBy7 iJf8WcRj6Icuso+Ncxr7eXce8ZpOrrPpa/Oup+XwhCgiUhLxgEyDNbNFDJ76914FfISN piv4nl4f4xkFyoI9htnL8HGH/aIA6dtVrqRPL7/BOBYRIuWp4Aot8ogCmMR9I5PjJ1ww EQ== From: Boris Ostrovsky To: xen-devel@lists.xenproject.org Cc: iwj@xenproject.org, wl@xen.org, anthony.perard@citrix.com, jbeulich@suse.com, andrew.cooper3@citrix.com, roger.pau@citrix.com, jun.nakajima@intel.com, kevin.tian@intel.com, boris.ostrvsky@oracle.com Subject: [PATCH 2/4] x86: Introduce MSR_UNHANDLED Date: Thu, 7 Jan 2021 15:34:56 -0500 Message-Id: <1610051698-23675-3-git-send-email-boris.ostrovsky@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1610051698-23675-1-git-send-email-boris.ostrovsky@oracle.com> References: <1610051698-23675-1-git-send-email-boris.ostrovsky@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9857 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 malwarescore=0 mlxscore=0 spamscore=0 mlxlogscore=999 phishscore=0 bulkscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101070120 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9857 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 bulkscore=0 clxscore=1015 spamscore=0 impostorscore=0 priorityscore=1501 mlxscore=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101070120 X-ZohoMail-DKIM: pass (identity @oracle.com) Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When toolstack updates MSR policy, this MSR offset (which is an invalid MSR index) is used to indicate hypervisor behavior when a guest accesses an MSR which is not explicitly emulated. Signed-off-by: Boris Ostrovsky --- xen/include/xen/lib/x86/msr.h | 17 ++++++++++++++++- xen/lib/x86/msr.c | 16 +++++++++------- 2 files changed, 25 insertions(+), 8 deletions(-) diff --git a/xen/include/xen/lib/x86/msr.h b/xen/include/xen/lib/x86/msr.h index 48ba4a59c036..7911ae31eb48 100644 --- a/xen/include/xen/lib/x86/msr.h +++ b/xen/include/xen/lib/x86/msr.h @@ -2,8 +2,21 @@ #ifndef XEN_LIB_X86_MSR_H #define XEN_LIB_X86_MSR_H =20 +/* + * Behavior on accesses to MSRs that are not handled by emulation: + * 0 =3D return #GP, warning emitted + * 1 =3D read as 0, writes are dropped, no warning + * 2 =3D read as 0, writes are dropped, warning emitted + */ +#define MSR_UNHANDLED_NEVER 0 +#define MSR_UNHANDLED_SILENT 1 +#define MSR_UNHANDLED_VERBOSE 2 + +/* MSR that is not explicitly processed by emulation */ +#define MSR_UNHANDLED -1 + /* Maximum number of MSRs written when serialising msr_policy. */ -#define MSR_MAX_SERIALISED_ENTRIES 2 +#define MSR_MAX_SERIALISED_ENTRIES 3 =20 /* MSR policy object for shared per-domain MSRs */ struct msr_policy @@ -45,6 +58,8 @@ struct msr_policy bool taa_no:1; }; } arch_caps; + + uint8_t ignore_msrs; }; =20 #ifdef __XEN__ diff --git a/xen/lib/x86/msr.c b/xen/lib/x86/msr.c index 7d71e92a380a..cf53768dfa4e 100644 --- a/xen/lib/x86/msr.c +++ b/xen/lib/x86/msr.c @@ -6,11 +6,11 @@ * Copy a single MSR into the provided msr_entry_buffer_t buffer, performi= ng a * boundary check against the buffer size. */ -static int copy_msr_to_buffer(uint32_t idx, uint64_t val, +static int copy_msr_to_buffer(uint32_t idx, uint64_t val, uint32_t flags, msr_entry_buffer_t msrs, uint32_t *curr_entry, const uint32_t nr_entr= ies) { - const xen_msr_entry_t ent =3D { .idx =3D idx, .val =3D val }; + const xen_msr_entry_t ent =3D { .idx =3D idx, .val =3D val, .flags =3D= flags }; =20 if ( *curr_entry =3D=3D nr_entries ) return -ENOBUFS; @@ -29,17 +29,18 @@ int x86_msr_copy_to_buffer(const struct msr_policy *p, const uint32_t nr_entries =3D *nr_entries_p; uint32_t curr_entry =3D 0; =20 -#define COPY_MSR(idx, val) \ +#define COPY_MSR(idx, val, flags) \ ({ \ int ret; \ \ if ( (ret =3D copy_msr_to_buffer( \ - idx, val, msrs, &curr_entry, nr_entries)) ) \ + idx, val, flags, msrs, &curr_entry, nr_entries)) ) \ return ret; \ }) =20 - COPY_MSR(MSR_INTEL_PLATFORM_INFO, p->platform_info.raw); - COPY_MSR(MSR_ARCH_CAPABILITIES, p->arch_caps.raw); + COPY_MSR(MSR_INTEL_PLATFORM_INFO, p->platform_info.raw, 0); + COPY_MSR(MSR_ARCH_CAPABILITIES, p->arch_caps.raw, 0); + COPY_MSR(MSR_UNHANDLED, 0, p->ignore_msrs); =20 #undef COPY_MSR =20 @@ -77,7 +78,7 @@ int x86_msr_copy_from_buffer(struct msr_policy *p, if ( copy_from_buffer_offset(&data, msrs, i, 1) ) return -EFAULT; =20 - if ( data.flags ) /* .flags MBZ */ + if ( data.idx !=3D MSR_UNHANDLED && data.flags ) { rc =3D -EINVAL; goto err; @@ -101,6 +102,7 @@ int x86_msr_copy_from_buffer(struct msr_policy *p, =20 case MSR_INTEL_PLATFORM_INFO: ASSIGN(platform_info.raw); break; case MSR_ARCH_CAPABILITIES: ASSIGN(arch_caps.raw); break; + case MSR_UNHANDLED: p->ignore_msrs =3D data.flags & 0xff= ; break; =20 #undef ASSIGN =20 --=20 1.8.3.1