From 03b9a6e18d325ede28c6dc218cedda53969eb41b Mon Sep 17 00:00:00 2001 From: Zhao Liu Date: Thu, 20 Oct 2022 16:38:20 +0800 Subject: x86/hyperv: Remove BUG_ON() for kmap_local_page() The commit 154fb14df7a3c ("x86/hyperv: Replace kmap() with kmap_local_page()") keeps the BUG_ON() to check if kmap_local_page() fails. But in fact, kmap_local_page() always returns a valid kernel address and won't return NULL here. It will BUG on its own if it fails. [1] So directly use memcpy_to_page() which creates local mapping to copy. [1]: https://lore.kernel.org/lkml/YztFEyUA48et0yTt@iweiny-mobl/ Suggested-by: Fabio M. De Francesco Suggested-by: Ira Weiny Reviewed-by: Ira Weiny Signed-off-by: Zhao Liu Link: https://lore.kernel.org/r/20221020083820.2341088-1-zhao1.liu@linux.intel.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 29774126e931..d46f70522ddf 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -444,7 +444,7 @@ void __init hyperv_init(void) if (hv_root_partition) { struct page *pg; - void *src, *dst; + void *src; /* * For the root partition, the hypervisor will set up its @@ -459,13 +459,11 @@ void __init hyperv_init(void) wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); pg = vmalloc_to_page(hv_hypercall_pg); - dst = kmap_local_page(pg); src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE, MEMREMAP_WB); - BUG_ON(!(src && dst)); - memcpy(dst, src, HV_HYP_PAGE_SIZE); + BUG_ON(!src); + memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE); memunmap(src); - kunmap_local(dst); } else { hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); -- cgit v1.2.3-70-g09d2 From 2982635a0b3d08d6fee2ff05632206286df0e703 Mon Sep 17 00:00:00 2001 From: Anirudh Rayabharam Date: Thu, 27 Oct 2022 15:27:29 +0530 Subject: x86/hyperv: fix invalid writes to MSRs during root partition kexec hyperv_cleanup resets the hypercall page by setting the MSR to 0. However, the root partition is not allowed to write to the GPA bits of the MSR. Instead, it uses the hypercall page provided by the MSR. Similar is the case with the reference TSC MSR. Clear only the enable bit instead of zeroing the entire MSR to make the code valid for root partition too. Signed-off-by: Anirudh Rayabharam Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20221027095729.1676394-3-anrayabh@linux.microsoft.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_init.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index d46f70522ddf..f49bc3ec76e6 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -535,6 +535,7 @@ common_free: void hyperv_cleanup(void) { union hv_x64_msr_hypercall_contents hypercall_msr; + union hv_reference_tsc_msr tsc_msr; unregister_syscore_ops(&hv_syscore_ops); @@ -550,12 +551,14 @@ void hyperv_cleanup(void) hv_hypercall_pg = NULL; /* Reset the hypercall page */ - hypercall_msr.as_uint64 = 0; - wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + hypercall_msr.as_uint64 = hv_get_register(HV_X64_MSR_HYPERCALL); + hypercall_msr.enable = 0; + hv_set_register(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); /* Reset the TSC page */ - hypercall_msr.as_uint64 = 0; - wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); + tsc_msr.as_uint64 = hv_get_register(HV_X64_MSR_REFERENCE_TSC); + tsc_msr.enable = 0; + hv_set_register(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64); } void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) -- cgit v1.2.3-70-g09d2