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hv: hotfix for xsave

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In current code, XCR0 and XSS are not in default value during vcpu
launch, it will result in a warning in Linux:

     WARNING: CPU: 0 PID: 0 at arch/x86/kernel/fpu/xstate.c:614
     fpu__init_system_xstate+0x43a/0x878

 For security reason, we set XCR0 and XSS with feature bitmap get from
 CPUID, and run XRSTORS in context switch in. This make sure the XSAVE
 area to be fully in initiate state.
 But, before enter guest for the first time, XCR0 and XSS should be set to
 default value, as the guest kernel assume it.

Tracked-On: #4278
Signed-off-by: Conghui Chen <conghui.chen@intel.com>
This commit is contained in:
Conghui Chen 2019-12-10 16:31:50 +00:00 committed by wenlingz
parent 067d8536b2
commit 92ed860187
2 changed files with 8 additions and 0 deletions
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4
hypervisor/arch/x86/guest/vcpu.c
View File

@ -532,6 +532,10 @@ int32_t run_vcpu(struct acrn_vcpu *vcpu)
*/
flush_vpid_global();
/* Set XCR0 and XSS to default value */
write_xcr(0, XCR0_DEFAULT);
msr_write(MSR_IA32_XSS, XSS_DEFAULT);
/* Set vcpu launched */
vcpu->launched = true;

4
hypervisor/include/arch/x86/cpu.h
View File

@ -85,6 +85,8 @@
#define CR4_SMAP (1UL<<21U)
#define CR4_PKE (1UL<<22U) /* Protect-key-enable */
/* XCR0_FPU */
#define XCR0_FPU (1UL<<0U)
/* XCR0_SSE */
#define XCR0_SSE (1UL<<1U)
/* XCR0_AVX */
@ -100,6 +102,8 @@
*/
#define XCR0_RESERVED_BITS ((~((1UL << 10U) - 1UL)) | (1UL << 8U))
#define XCR0_DEFAULT (XCR0_FPU)
#define XSS_DEFAULT (0U)
/*
* Entries in the Interrupt Descriptor Table (IDT)