File xsa435-0-10.patch of Package xen.35285

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File xsa435-0-10.patch of Package xen.35285

From e83cd54611fec5b7a539fa1281a14319143490e6 Mon Sep 17 00:00:00 2001
From: Jason Andryuk <jandryuk@gmail.com>
Date: Tue, 19 Jul 2022 16:08:15 -0400
Subject: x86: Expose more MSR_ARCH_CAPS to hwdom

commit e46474278a0e ("x86/intel: Expose MSR_ARCH_CAPS to dom0") started
exposing MSR_ARCH_CAPS to dom0.  More bits in MSR_ARCH_CAPS have since
been defined, but they haven't been exposed.  Update the list to allow
them through.

As one example, this allows a Linux Dom0 to know that it has the
appropriate microcode via FB_CLEAR.  Notably, and with the updated
microcode, this changes dom0's
/sys/devices/system/cpu/vulnerabilities/mmio_stale_data changes from:

"Vulnerable: Clear CPU buffers attempted, no microcode; SMT Host state unknown"

to:

"Mitigation: Clear CPU buffers; SMT Host state unknown"

This exposes the MMIO Stale Data and Intel Branch History Injection
(BHI) controls as well as the page size change MCE issue bit.

Fixes: commit 2ebe8fe9b7e0 ("x86/spec-ctrl: Enumeration for MMIO Stale Data controls")
Fixes: commit cea9ae062295 ("x86/spec-ctrl: Enumeration for new Intel BHI controls")
Fixes: commit 59e89cdabc71 ("x86/vtx: Disable executable EPT superpages to work around CVE-2018-12207")
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -63,7 +63,9 @@ static void __init calculate_host_policy
     mp->arch_caps.raw &=
         (ARCH_CAPS_RDCL_NO | ARCH_CAPS_IBRS_ALL | ARCH_CAPS_RSBA |
          ARCH_CAPS_SKIP_L1DFL | ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO |
-         ARCH_CAPS_IF_PSCHANGE_MC_NO | ARCH_CAPS_TSX_CTRL | ARCH_CAPS_TAA_NO);
+         ARCH_CAPS_IF_PSCHANGE_MC_NO | ARCH_CAPS_TSX_CTRL | ARCH_CAPS_TAA_NO |
+         ARCH_CAPS_SBDR_SSDP_NO | ARCH_CAPS_FBSDP_NO | ARCH_CAPS_PSDP_NO |
+         ARCH_CAPS_FB_CLEAR | ARCH_CAPS_RRSBA | ARCH_CAPS_BHI_NO);
 }
 
 static void __init calculate_hvm_max_policy(void)
@@ -124,7 +126,10 @@ int init_domain_msr_policy(struct domain
 
         mp->arch_caps.raw = val &
             (ARCH_CAPS_RDCL_NO | ARCH_CAPS_IBRS_ALL | ARCH_CAPS_RSBA |
-             ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO | ARCH_CAPS_TAA_NO);
+             ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO | ARCH_CAPS_IF_PSCHANGE_MC_NO |
+             ARCH_CAPS_TAA_NO | ARCH_CAPS_SBDR_SSDP_NO | ARCH_CAPS_FBSDP_NO |
+             ARCH_CAPS_PSDP_NO | ARCH_CAPS_FB_CLEAR | ARCH_CAPS_RRSBA |
+             ARCH_CAPS_BHI_NO);
     }
 
     d->arch.msr = mp;
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -61,6 +61,8 @@
 #define ARCH_CAPS_PSDP_NO		(_AC(1, ULL) << 15)
 #define ARCH_CAPS_FB_CLEAR		(_AC(1, ULL) << 17)
 #define ARCH_CAPS_FB_CLEAR_CTRL		(_AC(1, ULL) << 18)
+#define ARCH_CAPS_RRSBA			(_AC(1, ULL) << 19)
+#define ARCH_CAPS_BHI_NO		(_AC(1, ULL) << 20)
 
 #define MSR_FLUSH_CMD			0x0000010b
 #define FLUSH_CMD_L1D			(_AC(1, ULL) << 0)

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File xsa435-0-10.patch of Package xen.35285

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