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authorSaurabh Sengar <ssengar@linux.microsoft.com>2024-01-15 20:57:40 +0300
committerSasha Levin <sashal@kernel.org>2024-03-27 01:19:15 +0300
commit2984f26a4604dbd8d59171e0ae01daf4581e544f (patch)
tree2c84622fcc0a665421211ce68ffe120d308480b6 /arch/x86
parenta9fcd576b7128951aaab9cf4895ed5762ca24f76 (diff)
downloadlinux-2984f26a4604dbd8d59171e0ae01daf4581e544f.tar.xz
x86/hyperv: Allow 15-bit APIC IDs for VTL platforms
[ Upstream commit 0d63e4c0ebc2b5c329babde44fd61d3f08db814d ] The current method for signaling the compatibility of a Hyper-V host with MSIs featuring 15-bit APIC IDs relies on a synthetic cpuid leaf. However, for higher VTLs, this leaf is not reported, due to the absence of an IO-APIC. As an alternative, assume that when running at a high VTL, the host supports 15-bit APIC IDs. This assumption is safe, as Hyper-V does not employ any architectural MSIs at higher VTLs This unblocks startup of VTL2 environments with more than 256 CPUs. Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/1705341460-18394-1-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <1705341460-18394-1-git-send-email-ssengar@linux.microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/hyperv/hv_vtl.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 999f5ac82fe9..53b309d41b3b 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -16,6 +16,11 @@
extern struct boot_params boot_params;
static struct real_mode_header hv_vtl_real_mode_header;
+static bool __init hv_vtl_msi_ext_dest_id(void)
+{
+ return true;
+}
+
void __init hv_vtl_init_platform(void)
{
pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
@@ -38,6 +43,8 @@ void __init hv_vtl_init_platform(void)
x86_platform.legacy.warm_reset = 0;
x86_platform.legacy.reserve_bios_regions = 0;
x86_platform.legacy.devices.pnpbios = 0;
+
+ x86_init.hyper.msi_ext_dest_id = hv_vtl_msi_ext_dest_id;
}
static inline u64 hv_vtl_system_desc_base(struct ldttss_desc *desc)